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// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/ui/views/tabs/tab_strip.h"
#include <stddef.h>
#include <algorithm>
#include <iterator>
#include <limits>
#include <string>
#include <utility>
#include <vector>
#include "base/bind.h"
#include "base/callback.h"
#include "base/compiler_specific.h"
#include "base/containers/adapters.h"
#include "base/containers/contains.h"
#include "base/containers/flat_map.h"
#include "base/feature_list.h"
#include "base/i18n/rtl.h"
#include "base/memory/weak_ptr.h"
#include "base/metrics/histogram.h"
#include "base/metrics/histogram_functions.h"
#include "base/metrics/histogram_macros.h"
#include "base/metrics/user_metrics.h"
#include "base/no_destructor.h"
#include "base/numerics/ranges.h"
#include "base/numerics/safe_conversions.h"
#include "base/strings/string_piece.h"
#include "base/strings/utf_string_conversions.h"
#include "base/timer/elapsed_timer.h"
#include "build/build_config.h"
#include "build/chromeos_buildflags.h"
#include "chrome/browser/defaults.h"
#include "chrome/browser/themes/theme_properties.h"
#include "chrome/browser/ui/layout_constants.h"
#include "chrome/browser/ui/tabs/tab_group_theme.h"
#include "chrome/browser/ui/tabs/tab_strip_model.h"
#include "chrome/browser/ui/tabs/tab_types.h"
#include "chrome/browser/ui/ui_features.h"
#include "chrome/browser/ui/view_ids.h"
#include "chrome/browser/ui/views/frame/browser_view.h"
#include "chrome/browser/ui/views/tabs/browser_tab_strip_controller.h"
#include "chrome/browser/ui/views/tabs/stacked_tab_strip_layout.h"
#include "chrome/browser/ui/views/tabs/tab.h"
#include "chrome/browser/ui/views/tabs/tab_drag_controller.h"
#include "chrome/browser/ui/views/tabs/tab_group_header.h"
#include "chrome/browser/ui/views/tabs/tab_group_highlight.h"
#include "chrome/browser/ui/views/tabs/tab_group_underline.h"
#include "chrome/browser/ui/views/tabs/tab_group_views.h"
#include "chrome/browser/ui/views/tabs/tab_hover_card_bubble_view.h"
#include "chrome/browser/ui/views/tabs/tab_slot_view.h"
#include "chrome/browser/ui/views/tabs/tab_strip_controller.h"
#include "chrome/browser/ui/views/tabs/tab_strip_layout_helper.h"
#include "chrome/browser/ui/views/tabs/tab_strip_layout_types.h"
#include "chrome/browser/ui/views/tabs/tab_strip_observer.h"
#include "chrome/browser/ui/views/tabs/tab_style_views.h"
#include "chrome/browser/ui/views/touch_uma/touch_uma.h"
#include "chrome/browser/ui/web_applications/app_browser_controller.h"
#include "chrome/grit/generated_resources.h"
#include "chrome/grit/theme_resources.h"
#include "components/tab_groups/tab_group_color.h"
#include "components/tab_groups/tab_group_id.h"
#include "components/tab_groups/tab_group_visual_data.h"
#include "third_party/skia/include/core/SkColorFilter.h"
#include "third_party/skia/include/core/SkPath.h"
#include "third_party/skia/include/effects/SkLayerDrawLooper.h"
#include "third_party/skia/include/pathops/SkPathOps.h"
#include "ui/base/clipboard/clipboard.h"
#include "ui/base/dragdrop/drag_drop_types.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/base/models/list_selection_model.h"
#include "ui/base/resource/resource_bundle.h"
#include "ui/base/theme_provider.h"
#include "ui/display/display.h"
#include "ui/display/screen.h"
#include "ui/gfx/animation/throb_animation.h"
#include "ui/gfx/animation/tween.h"
#include "ui/gfx/geometry/rect_conversions.h"
#include "ui/gfx/geometry/size.h"
#include "ui/gfx/image/image_skia.h"
#include "ui/gfx/image/image_skia_operations.h"
#include "ui/gfx/native_widget_types.h"
#include "ui/gfx/range/range.h"
#include "ui/gfx/skia_util.h"
#include "ui/views/accessibility/view_accessibility.h"
#include "ui/views/controls/image_view.h"
#include "ui/views/masked_targeter_delegate.h"
#include "ui/views/metadata/metadata_impl_macros.h"
#include "ui/views/mouse_watcher_view_host.h"
#include "ui/views/rect_based_targeting_utils.h"
#include "ui/views/view_model_utils.h"
#include "ui/views/view_observer.h"
#include "ui/views/view_targeter.h"
#include "ui/views/view_utils.h"
#include "ui/views/widget/root_view.h"
#include "ui/views/widget/widget.h"
#include "ui/views/window/non_client_view.h"
#if defined(OS_WIN)
#include "base/win/windows_version.h"
#include "ui/display/win/screen_win.h"
#include "ui/gfx/win/hwnd_util.h"
#include "ui/views/win/hwnd_util.h"
#if defined(USE_AURA)
#include "ui/aura/window.h"
namespace {
// Distance from the next/previous stacked before before we consider the tab
// close enough to trigger moving.
const int kStackedDistance = 36;
// Given the bounds of a dragged tab, return the X coordinate to use for
// computing where in the strip to insert/move the tab.
int GetDraggedX(const gfx::Rect& dragged_bounds) {
return dragged_bounds.x() + TabStyle::GetTabInternalPadding().left();
// Max number of stacked tabs.
constexpr int kMaxStackedCount = 4;
// Padding between stacked tabs.
constexpr int kStackedPadding = 6;
// Size of the drop indicator.
int g_drop_indicator_width = 0;
int g_drop_indicator_height = 0;
// Listens in on the browser event stream (as a pre target event handler) and
// hides an associated hover card on any keypress.
class TabHoverCardEventSniffer : public ui::EventHandler {
// On Mac, events should be added to the root view.
#if defined(OS_MAC)
using OwnerView = views::View*;
#else // defined(OS_MAC)
using OwnerView = gfx::NativeWindow;
#endif // defined(OS_MAC)
TabHoverCardEventSniffer(TabHoverCardBubbleView* hover_card,
TabStrip* tab_strip)
: hover_card_(hover_card),
#if defined(OS_MAC)
owner_view_(tab_strip->GetWidget()->GetRootView()) {
#else // defined(OS_MAC)
owner_view_(tab_strip->GetWidget()->GetNativeWindow()) {
#endif // defined(OS_MAC)
~TabHoverCardEventSniffer() override {
void AddPreTargetHandler() {
if (owner_view_)
void RemovePreTargetHandler() {
if (owner_view_)
// ui::EventTarget:
void OnKeyEvent(ui::KeyEvent* event) override {
if (!tab_strip_->IsFocusInTabs())
void OnMouseEvent(ui::MouseEvent* event) override {
if (event->IsAnyButton())
void OnGestureEvent(ui::GestureEvent* event) override {
base::StringPiece GetLogContext() const override {
return "TabHoverCardEventSniffer";
TabHoverCardBubbleView* const hover_card_;
TabStrip* tab_strip_;
const OwnerView owner_view_;
// Provides the ability to monitor when a tab's bounds have been animated. Used
// to hook callbacks to adjust things like tabstrip preferred size and tab group
// underlines.
class TabSlotAnimationDelegate : public gfx::AnimationDelegate {
using OnAnimationProgressedCallback =
TabStrip* tab_strip,
TabSlotView* slot_view,
OnAnimationProgressedCallback on_animation_progressed);
TabSlotAnimationDelegate(const TabSlotAnimationDelegate&) = delete;
TabSlotAnimationDelegate& operator=(const TabSlotAnimationDelegate&) = delete;
~TabSlotAnimationDelegate() override;
void AnimationProgressed(const gfx::Animation* animation) override;
TabStrip* tab_strip() { return tab_strip_; }
TabSlotView* slot_view() { return slot_view_; }
TabStrip* const tab_strip_;
TabSlotView* const slot_view_;
OnAnimationProgressedCallback on_animation_progressed_;
TabStrip* tab_strip,
TabSlotView* slot_view,
OnAnimationProgressedCallback on_animation_progressed)
: tab_strip_(tab_strip),
on_animation_progressed_(on_animation_progressed) {}
TabSlotAnimationDelegate::~TabSlotAnimationDelegate() = default;
void TabSlotAnimationDelegate::AnimationProgressed(
const gfx::Animation* animation) {
// Animation delegate used when a dragged tab is released. When done sets the
// dragging state to false.
class ResetDraggingStateDelegate : public TabSlotAnimationDelegate {
TabStrip* tab_strip,
Tab* tab,
OnAnimationProgressedCallback on_animation_progressed);
ResetDraggingStateDelegate(const ResetDraggingStateDelegate&) = delete;
ResetDraggingStateDelegate& operator=(const ResetDraggingStateDelegate&) =
~ResetDraggingStateDelegate() override;
void AnimationEnded(const gfx::Animation* animation) override;
void AnimationCanceled(const gfx::Animation* animation) override;
TabStrip* tab_strip,
Tab* tab,
OnAnimationProgressedCallback on_animation_progressed)
: TabSlotAnimationDelegate(tab_strip, tab, on_animation_progressed) {}
ResetDraggingStateDelegate::~ResetDraggingStateDelegate() = default;
void ResetDraggingStateDelegate::AnimationEnded(
const gfx::Animation* animation) {
void ResetDraggingStateDelegate::AnimationCanceled(
const gfx::Animation* animation) {
// If |dest| contains the point |point_in_source| the event handler from |dest|
// is returned. Otherwise returns null.
views::View* ConvertPointToViewAndGetEventHandler(
views::View* source,
views::View* dest,
const gfx::Point& point_in_source) {
gfx::Point dest_point(point_in_source);
views::View::ConvertPointToTarget(source, dest, &dest_point);
return dest->HitTestPoint(dest_point)
? dest->GetEventHandlerForPoint(dest_point)
: nullptr;
// Gets a tooltip handler for |point_in_source| from |dest|. Note that |dest|
// should return null if it does not contain the point.
views::View* ConvertPointToViewAndGetTooltipHandler(
views::View* source,
views::View* dest,
const gfx::Point& point_in_source) {
gfx::Point dest_point(point_in_source);
views::View::ConvertPointToTarget(source, dest, &dest_point);
return dest->GetTooltipHandlerForPoint(dest_point);
TabDragController::EventSource EventSourceFromEvent(
const ui::LocatedEvent& event) {
return event.IsGestureEvent() ? TabDragController::EVENT_SOURCE_TOUCH
: TabDragController::EVENT_SOURCE_MOUSE;
int GetStackableTabWidth() {
return TabStyle::GetTabOverlap() +
(ui::TouchUiController::Get()->touch_ui() ? 136 : 102);
} // namespace
// TabStrip::RemoveTabDelegate
// AnimationDelegate used when removing a tab. Does the necessary cleanup when
// done.
class TabStrip::RemoveTabDelegate : public TabSlotAnimationDelegate {
RemoveTabDelegate(TabStrip* tab_strip,
Tab* tab,
OnAnimationProgressedCallback on_animation_progressed);
RemoveTabDelegate(const RemoveTabDelegate&) = delete;
RemoveTabDelegate& operator=(const RemoveTabDelegate&) = delete;
void AnimationEnded(const gfx::Animation* animation) override;
void AnimationCanceled(const gfx::Animation* animation) override;
TabStrip* tab_strip,
Tab* tab,
OnAnimationProgressedCallback on_animation_progressed)
: TabSlotAnimationDelegate(tab_strip, tab, on_animation_progressed) {}
void TabStrip::RemoveTabDelegate::AnimationEnded(
const gfx::Animation* animation) {
void TabStrip::RemoveTabDelegate::AnimationCanceled(
const gfx::Animation* animation) {
// TabStrip::TabDragContextImpl
class TabStrip::TabDragContextImpl : public TabDragContext {
explicit TabDragContextImpl(TabStrip* tab_strip) : tab_strip_(tab_strip) {}
bool IsDragStarted() const {
return drag_controller_ && drag_controller_->started_drag();
bool IsMutating() const {
return drag_controller_ && drag_controller_->is_mutating();
bool IsDraggingWindow() const {
return drag_controller_ && drag_controller_->is_dragging_window();
bool IsDraggingTab(content::WebContents* contents) const {
return contents && drag_controller_ &&
void SetMoveBehavior(TabDragController::MoveBehavior move_behavior) {
if (drag_controller_)
void MaybeStartDrag(TabSlotView* source,
const ui::LocatedEvent& event,
const ui::ListSelectionModel& original_selection) {
std::vector<TabSlotView*> dragging_views;
int x = source->GetMirroredXInView(event.x());
int y = event.y();
// Build the set of selected tabs to drag and calculate the offset from the
// source.
ui::ListSelectionModel selection_model;
if (source->GetTabSlotViewType() ==
TabSlotView::ViewType::kTabGroupHeader) {
const gfx::Range grouped_tabs =
for (auto index = grouped_tabs.start(); index < grouped_tabs.end();
++index) {
// Set |selection_model| if and only if the original selection does not
// match the group exactly. See TabDragController::Init() for details
// on how |selection_model| is used.
if (!original_selection.IsSelected(index))
selection_model = original_selection;
if (grouped_tabs.length() != original_selection.size())
selection_model = original_selection;
} else {
for (int i = 0; i < GetTabCount(); ++i) {
Tab* other_tab = GetTabAt(i);
if (tab_strip_->IsTabSelected(other_tab)) {
if (other_tab == source)
x += GetSizeNeededForViews(dragging_views) - other_tab->width();
if (!original_selection.IsSelected(tab_strip_->GetModelIndexOf(source)))
selection_model = original_selection;
DCHECK(base::Contains(dragging_views, source));
// Delete the existing DragController before creating a new one. We do this
// as creating the DragController remembers the WebContents delegates and we
// need to make sure the existing DragController isn't still a delegate.
TabDragController::MoveBehavior move_behavior = TabDragController::REORDER;
// Use MOVE_VISIBLE_TABS in the following conditions:
// . Mouse event generated from touch and the left button is down (the right
// button corresponds to a long press, which we want to reorder).
// . Gesture tap down and control key isn't down.
// . Real mouse event and control is down. This is mostly for testing.
DCHECK(event.type() == ui::ET_MOUSE_PRESSED ||
event.type() == ui::ET_GESTURE_TAP_DOWN ||
event.type() == ui::ET_GESTURE_SCROLL_BEGIN);
if (tab_strip_->touch_layout_ &&
((event.type() == ui::ET_MOUSE_PRESSED &&
(((event.flags() & ui::EF_FROM_TOUCH) &&
static_cast<const ui::MouseEvent&>(event).IsLeftMouseButton()) ||
(!(event.flags() & ui::EF_FROM_TOUCH) &&
static_cast<const ui::MouseEvent&>(event).IsControlDown()))) ||
(event.type() == ui::ET_GESTURE_TAP_DOWN && !event.IsControlDown()) ||
(event.type() == ui::ET_GESTURE_SCROLL_BEGIN &&
!event.IsControlDown()))) {
move_behavior = TabDragController::MOVE_VISIBLE_TABS;
drag_controller_ = std::make_unique<TabDragController>();
drag_controller_->Init(this, source, dragging_views, gfx::Point(x, y),
event.x(), std::move(selection_model), move_behavior,
void ContinueDrag(views::View* view, const ui::LocatedEvent& event) {
if (drag_controller_.get() &&
drag_controller_->event_source() == EventSourceFromEvent(event)) {
gfx::Point screen_location(event.location());
views::View::ConvertPointToScreen(view, &screen_location);
// Note: |tab_strip_| can be destroyed during drag, also destroying
// |this|.
base::WeakPtr<TabDragContext> weak_ptr(weak_factory_.GetWeakPtr());
if (!weak_ptr)
// Note: |drag_controller| can be set to null during the drag above.
if (drag_controller_ && drag_controller_->group())
bool EndDrag(EndDragReason reason) {
if (!drag_controller_.get())
return false;
bool started_drag = drag_controller_->started_drag();
return started_drag;
// TabDragContext:
views::View* AsView() override { return tab_strip_; }
const views::View* AsView() const override { return tab_strip_; }
Tab* GetTabAt(int i) const override { return tab_strip_->tab_at(i); }
int GetIndexOf(const TabSlotView* view) const override {
return tab_strip_->GetModelIndexOf(view);
int GetTabCount() const override { return tab_strip_->GetTabCount(); }
bool IsTabPinned(const Tab* tab) const override {
return tab_strip_->IsTabPinned(tab);
int GetPinnedTabCount() const override {
return tab_strip_->GetPinnedTabCount();
TabGroupHeader* GetTabGroupHeader(
const tab_groups::TabGroupId& group) const override {
return tab_strip_->group_header(group);
TabStripModel* GetTabStripModel() override {
return static_cast<BrowserTabStripController*>(
base::Optional<int> GetActiveTouchIndex() const override {
if (!tab_strip_->touch_layout_)
return base::nullopt;
return tab_strip_->touch_layout_->active_index();
TabDragController* GetDragController() override {
return drag_controller_.get();
void OwnDragController(TabDragController* controller) override {
// Typically, ReleaseDragController() and OwnDragController() calls are
// paired via corresponding calls to TabDragController::Detach() and
// TabDragController::Attach(). There is one exception to that rule: when a
// drag might start, we create a TabDragController that is owned by the
// potential source tabstrip in MaybeStartDrag(). If a drag actually starts,
// we then call Attach() on the source tabstrip, but since the source
// tabstrip already owns the TabDragController, so we don't need to do
// anything.
if (drag_controller_.get() != controller)
void DestroyDragController() override {
TabDragController* ReleaseDragController() override {
return drag_controller_.release();
bool IsDragSessionActive() const override {
return drag_controller_ != nullptr;
bool IsActiveDropTarget() const override {
for (int i = 0; i < GetTabCount(); ++i) {
const Tab* const tab = GetTabAt(i);
if (tab->dragging())
return true;
return false;
std::vector<int> GetTabXCoordinates() const override {
std::vector<int> results;
for (int i = 0; i < GetTabCount(); ++i)
return results;
int GetActiveTabWidth() const override {
return tab_strip_->GetActiveTabWidth();
int GetTabDragAreaWidth() const override {
// There are two cases here (with tab scrolling enabled):
// 1) If the tab strip is not wider than the tab strip region (and thus
// not scrollable), returning the available width for tabs rather than the
// actual width for tabs allows tabs to be dragged past the current bounds
// of the tabstrip, anywhere along the tab strip region.
// N.B. The available width for tabs in this case needs to ignore tab
// closing mode.
// 2) If the tabstrip is wider than the tab strip region (and thus is
// scrollable), returning the tabstrip width allows tabs to be dragged
// anywhere within the tabstrip, not just in the leftmost region of it.
return std::max(tab_strip_->GetAvailableWidthForTabStrip(),
int TabDragAreaBeginX() const override {
return tab_strip_->GetMirroredXWithWidthInView(0, GetTabDragAreaWidth());
int TabDragAreaEndX() const override {
return TabDragAreaBeginX() + GetTabDragAreaWidth();
int GetHorizontalDragThreshold() const override {
constexpr int kHorizontalMoveThreshold = 16; // DIPs.
// Stacked tabs in touch mode don't shrink.
if (tab_strip_->touch_layout_)
return kHorizontalMoveThreshold;
double ratio = double{tab_strip_->GetInactiveTabWidth()} /
return base::ClampRound(ratio * kHorizontalMoveThreshold);
int GetInsertionIndexForDraggedBounds(
const gfx::Rect& dragged_bounds,
std::vector<TabSlotView*> dragged_views,
int num_dragged_tabs,
bool mouse_has_ever_moved_left,
bool mouse_has_ever_moved_right,
base::Optional<tab_groups::TabGroupId> group) const override {
// If the strip has no tabs, the only position to insert at is 0.
if (!GetTabCount())
return 0;
base::Optional<int> index;
base::Optional<int> touch_index = GetActiveTouchIndex();
if (touch_index) {
index = GetInsertionIndexForDraggedBoundsStacked(
dragged_bounds, mouse_has_ever_moved_left,
if (index) {
// Only move the tab to the left/right if the user actually moved the
// mouse that way. This is necessary as tabs with stacked tabs
// before/after them have multiple drag positions.
if ((index < touch_index && !mouse_has_ever_moved_left) ||
(index > touch_index && !mouse_has_ever_moved_right)) {
index = *touch_index;
} else {
// If we're dragging a group by its header, the first element of
// |dragged_views| is a group header, and the second one is the first tab
// in that group.
int first_dragged_tab_index =
tab_strip_->GetModelIndexOf(dragged_views[group.has_value() ? 1 : 0]);
index = CalculateInsertionIndex(dragged_bounds, first_dragged_tab_index,
num_dragged_tabs, std::move(group));
if (!index) {
const int last_tab_right = ideal_bounds(GetTabCount() - 1).right();
index = (dragged_bounds.right() > last_tab_right) ? GetTabCount() : 0;
const Tab* last_visible_tab = tab_strip_->GetLastVisibleTab();
int last_insertion_point =
last_visible_tab ? (GetIndexOf(last_visible_tab) + 1) : 0;
// Clamp the insertion point to keep it within the visible region.
last_insertion_point = std::max(0, last_insertion_point - num_dragged_tabs);
// Ensure the first dragged tab always stays in the visible index range.
return std::min(*index, last_insertion_point);
bool ShouldDragToNextStackedTab(
const gfx::Rect& dragged_bounds,
int index,
bool mouse_has_ever_moved_right) const override {
if (index + 1 >= GetTabCount() ||
!tab_strip_->touch_layout_->IsStacked(index + 1) ||
return false;
int active_x = ideal_bounds(index).x();
int next_x = ideal_bounds(index + 1).x();
int mid_x =
std::min(next_x - kStackedDistance, active_x + (next_x - active_x) / 4);
return GetDraggedX(dragged_bounds) >= mid_x;
bool ShouldDragToPreviousStackedTab(
const gfx::Rect& dragged_bounds,
int index,
bool mouse_has_ever_moved_left) const override {
if (index - 1 < tab_strip_->GetPinnedTabCount() ||
!tab_strip_->touch_layout_->IsStacked(index - 1) ||
return false;
int active_x = ideal_bounds(index).x();
int previous_x = ideal_bounds(index - 1).x();
int mid_x = std::max(previous_x + kStackedDistance,
active_x - (active_x - previous_x) / 4);
return GetDraggedX(dragged_bounds) <= mid_x;
void DragActiveTabStacked(const std::vector<int>& initial_positions,
int delta) override {
DCHECK_EQ(GetTabCount(), int{initial_positions.size()});
std::vector<gfx::Rect> CalculateBoundsForDraggedViews(
const std::vector<TabSlotView*>& views) override {
std::vector<gfx::Rect> bounds;
const int overlap = TabStyle::GetTabOverlap();
int x = 0;
for (const TabSlotView* view : views) {
const int width = view->width();
bounds.push_back(gfx::Rect(x, 0, width, view->height()));
x += width - overlap;
return bounds;
void SetBoundsForDrag(const std::vector<TabSlotView*>& views,
const std::vector<gfx::Rect>& bounds) override {
DCHECK_EQ(views.size(), bounds.size());
for (size_t i = 0; i < views.size(); ++i)
// Ensure that the tab strip and its parent views are correctly re-laid out
// after repositioning dragged tabs. This avoids visual/layout issues such
// as
// Reset the layout size as we've effectively laid out a different size.
// This ensures a layout happens after the drag is done.
tab_strip_->last_layout_size_ = gfx::Size();
if (>group().has_value())
void StartedDragging(const std::vector<TabSlotView*>& views) override {
// Let the controller know that the user started dragging tabs.
views.size() == static_cast<size_t>(tab_strip_->GetModelCount()));
// Reset dragging state of existing tabs.
for (int i = 0; i < GetTabCount(); ++i)
for (size_t i = 0; i < views.size(); ++i) {
// Move the dragged tabs to their ideal bounds.
// Sets the bounds of the dragged tab slots.
for (TabSlotView* view : views) {
if (view->GetTabSlotViewType() ==
TabSlotView::ViewType::kTabGroupHeader) {
} else {
int tab_data_index = GetIndexOf(view);
DCHECK_NE(TabStripModel::kNoTab, tab_data_index);
void DraggedTabsDetached() override {
// Let the controller know that the user is not dragging this tabstrip's
// tabs anymore.
void StoppedDragging(const std::vector<TabSlotView*>& views,
const std::vector<int>& initial_positions,
bool move_only,
bool completed) override {
// Let the controller know that the user stopped dragging tabs.
if (move_only && tab_strip_->touch_layout_) {
if (completed)
bool is_first_view = true;
for (size_t i = 0; i < views.size(); ++i)
tab_strip_->StoppedDraggingView(views[i], &is_first_view);
void LayoutDraggedViewsAt(const std::vector<TabSlotView*>& views,
TabSlotView* source_view,
const gfx::Point& location,
bool initial_drag) override {
std::vector<gfx::Rect> bounds = CalculateBoundsForDraggedViews(views);
DCHECK_EQ(views.size(), bounds.size());
int active_tab_model_index = GetIndexOf(source_view);
int active_tab_index = static_cast<int>(
std::find(views.begin(), views.end(), source_view) - views.begin());
for (size_t i = 0; i < views.size(); ++i) {
TabSlotView* view = views[i];
gfx::Rect new_bounds = bounds[i];
new_bounds.Offset(location.x(), location.y());
int consecutive_index =
active_tab_model_index - (active_tab_index - static_cast<int>(i));
// If this is the initial layout during a drag and the tabs aren't
// consecutive animate the view into position. Do the same if the tab is
// already animating (which means we previously caused it to animate).
if ((initial_drag && GetIndexOf(views[i]) != consecutive_index) ||
tab_strip_->bounds_animator_.IsAnimating(views[i])) {
tab_strip_->bounds_animator_.SetTargetBounds(views[i], new_bounds);
} else {
// The rightmost tab may have moved, which would change the tabstrip's
// preferred width.
// Forces the entire tabstrip to lay out.
void ForceLayout() override {
gfx::Rect ideal_bounds(int i) const { return tab_strip_->ideal_bounds(i); }
gfx::Rect ideal_bounds(tab_groups::TabGroupId group) const {
return tab_strip_->ideal_bounds(group);
// Determines the index to move the dragged tabs to. The dragged tabs must
// already be in the tabstrip. |dragged_bounds| is the union of the bounds
// of the dragged tabs and group header, if any. |first_dragged_tab_index| is
// the current model index in this tabstrip of the first dragged tab. The
// dragged tabs must be in the tabstrip already!
int CalculateInsertionIndex(
const gfx::Rect& dragged_bounds,
int first_dragged_tab_index,
int num_dragged_tabs,
base::Optional<tab_groups::TabGroupId> dragged_group) const {
// This method assumes that the dragged tabs and group are already in the
// tabstrip (i.e. it doesn't support attaching a drag to a new tabstrip).
// This assumption is critical because it means that tab width won't change
// after this method's recommendation is implemented.
// For each possible insertion index, determine what the ideal bounds of
// the dragged tabs would be at that index. This corresponds to where they
// would slide to if the drag session ended now. We want to insert at the
// index that minimizes the distance between the corresponding ideal bounds
// and the current bounds of the tabs. This is equivalent to minimizing:
// - the distance of the aforementioned slide,
// - the width of the gaps in the tabstrip, or
// - the amount of tab overlap.
int min_distance_index = -1;
int min_distance = std::numeric_limits<int>::max();
for (int candidate_index = 0; candidate_index <= GetTabCount();
++candidate_index) {
if (!IsValidInsertionIndex(candidate_index, first_dragged_tab_index,
num_dragged_tabs, dragged_group)) {
// If there's a group header here, and we're dragging a group, we might
// end up on either side of that header. Check both cases to find the
// best option.
// TODO(tbergquist): Use this approach to determine if a tab should be
// added to the group. This is calculated elsewhere and may require some
// plumbing and/or duplicated code.
const int left_ideal_x = CalculateIdealX(
candidate_index, first_dragged_tab_index, dragged_bounds);
const int left_distance = std::abs(dragged_bounds.x() - left_ideal_x);
const int right_ideal_x =
left_ideal_x + CalculateIdealXAdjustmentIfAddedToGroup(
candidate_index, dragged_group);
const int right_distance = std::abs(dragged_bounds.x() - right_ideal_x);
const int distance = std::min(left_distance, right_distance);
if (distance < min_distance) {
min_distance = distance;
min_distance_index = candidate_index;
if (min_distance_index == -1) {
return 0;
// When moving a tab within a tabstrip, the target index is expressed as if
// the tabs are not in the tabstrip, i.e. it acts like the tabs are first
// removed and then re-inserted at the target index. We need to adjust the
// target index to account for this.
if (min_distance_index > first_dragged_tab_index)
min_distance_index -= num_dragged_tabs;
return min_distance_index;
// Dragging can't insert tabs into some indices.
bool IsValidInsertionIndex(
int candidate_index,
int first_dragged_tab_index,
int num_dragged_tabs,
base::Optional<tab_groups::TabGroupId> dragged_group) const {
if (candidate_index == 0)
return true;
// If |candidate_index| is right after one of the tabs we're dragging,
// inserting here would be nonsensical - we can't insert the dragged tabs
// into the middle of the dragged tabs. That's just silly.
if (candidate_index > first_dragged_tab_index &&
candidate_index <= first_dragged_tab_index + num_dragged_tabs) {
return false;
// This might be in the middle of a group, which may or may not be fine.
base::Optional<tab_groups::TabGroupId> left_group =
GetTabAt(candidate_index - 1)->group();
base::Optional<tab_groups::TabGroupId> right_group =
? GetTabAt(candidate_index)->group()
: base::nullopt;
if (left_group.has_value() && left_group == right_group) {
// Can't drag a group into another group.
if (dragged_group.has_value())
return false;
// Can't drag a tab into a collapsed group.
if (tab_strip_->controller()->IsGroupCollapsed(left_group.value()))
return false;
return true;
// Determines the x position that the dragged tabs would have if they were
// inserted at |candidate_index|. If there's a group header at that index,
// this assumes the dragged tabs *would not* be inserted into the group,
// and would therefore end up to the left of that header.
int CalculateIdealX(int candidate_index,
int first_dragged_tab_index,
gfx::Rect dragged_bounds) const {
if (candidate_index == 0)
return 0;
const int tab_overlap = TabStyle::GetTabOverlap();
// We'll insert just right of the tab at |candidate_index| - 1.
int ideal_x = ideal_bounds(candidate_index - 1).right();
// If the dragged tabs are currently left of |candidate_index|, moving
// them to |candidate_index| would move the tab at |candidate_index| - 1
// to the left by |num_dragged_tabs| slots. This would change the ideal x
// for the dragged tabs, as well, by the width of the dragged tabs.
if (candidate_index - 1 > first_dragged_tab_index)
ideal_x -= dragged_bounds.width() - tab_overlap;
return ideal_x - tab_overlap;
// There might be a group starting at |candidate_index|. If there is,
// this determines how the ideal x would change if the dragged tabs were
// added to that group, thereby moving them to that header's right.
int CalculateIdealXAdjustmentIfAddedToGroup(
int candidate_index,
base::Optional<tab_groups::TabGroupId> dragged_group) const {
// If the tab to the right of |candidate_index| is the first tab in a
// (non-collapsed) group, we are sharing this model index with a group
// header. We might end up on either side of it, so we need to check
// both positions.
if (!dragged_group.has_value() &&
tab_strip_->IsValidModelIndex(candidate_index)) {
base::Optional<tab_groups::TabGroupId> left_group =
tab_strip_->IsValidModelIndex(candidate_index - 1)
? GetTabAt(candidate_index - 1)->group()
: base::nullopt;
base::Optional<tab_groups::TabGroupId> right_group =
if (right_group.has_value() && left_group != right_group) {
if (tab_strip_->controller()->IsGroupCollapsed(right_group.value()))
return 0;
const int header_width =
GetTabGroupHeader(*right_group)->bounds().width() -
return header_width;
return 0;
// Used by GetInsertionIndexForDraggedBounds() when the tabstrip is stacked.
base::Optional<int> GetInsertionIndexForDraggedBoundsStacked(
const gfx::Rect& dragged_bounds,
bool mouse_has_ever_moved_left,
bool mouse_has_ever_moved_right) const {
int active_index = *GetActiveTouchIndex();
// Search from the active index to the front of the tabstrip. Do this as
// tabs overlap each other from the active index.
base::Optional<int> index =
GetInsertionIndexFromReversedStacked(dragged_bounds, active_index);
if (index != active_index)
return index;
if (!index)
return GetInsertionIndexFromStacked(dragged_bounds, active_index + 1);
// The position to drag to corresponds to the active tab. If the
// next/previous tab is stacked, then shorten the distance used to determine
// insertion bounds. We do this as GetInsertionIndexFrom() uses the bounds
// of the tabs. When tabs are stacked the next/previous tab is on top of the
// tab.
if (active_index + 1 < GetTabCount() &&
tab_strip_->touch_layout_->IsStacked(active_index + 1)) {
index = GetInsertionIndexFromStacked(dragged_bounds, active_index + 1);
if (!index && ShouldDragToNextStackedTab(dragged_bounds, active_index,
index = active_index + 1;
else if (index == -1)
index = active_index;
} else if (ShouldDragToPreviousStackedTab(dragged_bounds, active_index,
mouse_has_ever_moved_left)) {
index = active_index - 1;
return index;
// Determines the index to insert tabs at. |dragged_bounds| is the bounds of
// the tab being dragged and |start| is the index of the tab to start looking
// from. The search proceeds to the end of the strip.
base::Optional<int> GetInsertionIndexFromStacked(
const gfx::Rect& dragged_bounds,
int start) const {
const int last_tab = GetTabCount() - 1;
if (start < 0 || start > last_tab)
return base::nullopt;
const int dragged_x = GetDraggedX(dragged_bounds);
if (dragged_x < ideal_bounds(start).x() ||
dragged_x > ideal_bounds(last_tab).right()) {
return base::nullopt;
base::Optional<int> insertion_index;
for (int i = start; i <= last_tab; ++i) {
const gfx::Rect current_bounds = ideal_bounds(i);
int current_center = current_bounds.CenterPoint().x();
if (dragged_bounds.width() > current_bounds.width() &&
dragged_bounds.x() < current_bounds.x()) {
current_center -= (dragged_bounds.width() - current_bounds.width());
if (dragged_x < current_center) {
insertion_index = i;
if (!insertion_index.has_value())
return last_tab + 1;
return insertion_index;
// Like GetInsertionIndexFrom(), but searches backwards from |start| to the
// beginning of the strip.
base::Optional<int> GetInsertionIndexFromReversedStacked(
const gfx::Rect& dragged_bounds,
int start) const {
const int dragged_x = GetDraggedX(dragged_bounds);
if (start < 0 || start >= GetTabCount() ||
dragged_x >= ideal_bounds(start).right() ||
dragged_x < ideal_bounds(0).x())
return base::nullopt;
for (int i = start; i >= 0; --i) {
if (dragged_x >= ideal_bounds(i).CenterPoint().x())
return i + 1;
return 0;
// Sets the ideal bounds x-coordinates to |positions|.
void SetIdealBoundsFromPositions(const std::vector<int>& positions) {
if (static_cast<size_t>(GetTabCount()) != positions.size())
for (int i = 0; i < GetTabCount(); ++i) {
gfx::Rect bounds(ideal_bounds(i));
tab_strip_->tabs_.set_ideal_bounds(i, bounds);
TabStrip* const tab_strip_;
// The controller for a drag initiated from a Tab. Valid for the lifetime of
// the drag session.
std::unique_ptr<TabDragController> drag_controller_;
base::WeakPtrFactory<TabDragContext> weak_factory_{this};
// TabStrip, public:
TabStrip::TabStrip(std::unique_ptr<TabStripController> controller)
: controller_(std::move(controller)),
drag_context_(std::make_unique<TabDragContextImpl>(this)) {
TabStrip::~TabStrip() {
// The animations may reference the tabs. Shut down the animation before we
// delete the tabs.
// Disengage the drag controller before doing any additional cleanup. This
// call can interact with child views so we can't reliably do it during member
// destruction.
// Make sure we unhook ourselves as a message loop observer so that we don't
// crash in the case where the user closes the window after closing a tab
// but before moving the mouse.
// Since TabGroupViews expects be able to remove the views it creates, clear
// |group_views_| before removing the remaining children below.
// The child tabs may call back to us from their destructors. Delete them so
// that if they call back we aren't in a weird state.
void TabStrip::SetAvailableWidthCallback(
base::RepeatingCallback<int()> available_width_callback) {
available_width_callback_ = available_width_callback;
// static
int TabStrip::GetSizeNeededForViews(const std::vector<TabSlotView*>& views) {
int width = 0;
for (const TabSlotView* view : views)
width += view->width();
if (!views.empty())
width -= TabStyle::GetTabOverlap() * (views.size() - 1);
return width;
void TabStrip::AddObserver(TabStripObserver* observer) {
void TabStrip::RemoveObserver(TabStripObserver* observer) {
void TabStrip::FrameColorsChanged() {
for (int i = 0; i < GetTabCount(); ++i)
void TabStrip::SetBackgroundOffset(int background_offset) {
if (background_offset == background_offset_)
background_offset_ = background_offset;
OnPropertyChanged(&background_offset_, views::kPropertyEffectsPaint);
bool TabStrip::IsRectInWindowCaption(const gfx::Rect& rect) {
// If there is no control at this location, the hit is in the caption area.
const views::View* v = GetEventHandlerForRect(rect);
if (v == this)
return true;
// When the window has a top drag handle, a thin strip at the top of inactive
// tabs and the new tab button is treated as part of the window drag handle,
// to increase draggability. This region starts 1 DIP above the top of the
// separator.
const int drag_handle_extension = TabStyle::GetDragHandleExtension(height());
// Disable drag handle extension when tab shapes are visible.
bool extend_drag_handle = !controller_->IsFrameCondensed() &&
// A hit on the tab is not in the caption unless it is in the thin strip
// mentioned above.
const int tab_index = tabs_.GetIndexOfView(v);
if (IsValidModelIndex(tab_index)) {
Tab* tab = tab_at(tab_index);
gfx::Rect tab_drag_handle = tab->GetMirroredBounds();
return extend_drag_handle && !tab->IsActive() &&
// |v| is some other view (e.g. a close button in a tab) and therefore |rect|
// is in client area.
return false;
bool TabStrip::IsPositionInWindowCaption(const gfx::Point& point) {
return IsRectInWindowCaption(gfx::Rect(point, gfx::Size(1, 1)));
bool TabStrip::IsTabStripCloseable() const {
return !drag_context_->IsDragSessionActive();
bool TabStrip::IsTabStripEditable() const {
return !drag_context_->IsDragSessionActive() &&
bool TabStrip::IsTabCrashed(int tab_index) const {
return tab_at(tab_index)->data().IsCrashed();
bool TabStrip::TabHasNetworkError(int tab_index) const {
return tab_at(tab_index)->data().network_state == TabNetworkState::kError;
base::Optional<TabAlertState> TabStrip::GetTabAlertState(int tab_index) const {
return Tab::GetAlertStateToShow(tab_at(tab_index)->data().alert_state);
void TabStrip::UpdateLoadingAnimations(const base::TimeDelta& elapsed_time) {
for (int i = 0; i < GetTabCount(); i++)
void TabStrip::SetStackedLayout(bool stacked_layout) {
if (stacked_layout == stacked_layout_)
stacked_layout_ = stacked_layout;
// When transitioning to stacked try to keep the active tab from moving.
const int active_index = controller_->GetActiveIndex();
if (touch_layout_ && active_index != -1) {
for (int i = 0; i < GetTabCount(); ++i)
void TabStrip::AddTabAt(int model_index, TabRendererData data, bool is_active) {
Tab* tab = new Tab(this);
AddChildViewAt(tab, GetViewInsertionIndex(tab, base::nullopt, model_index));
const bool pinned = data.pinned;
tabs_.Add(tab, model_index);
// Setting data must come after all state from the model has been updated
// above for the tab. Accessibility, in particular, reacts to data changed
// callbacks.
if (touch_layout_) {
int add_types = 0;
if (pinned)
add_types |= StackedTabStripLayout::kAddTypePinned;
if (is_active)
add_types |= StackedTabStripLayout::kAddTypeActive;
touch_layout_->AddTab(model_index, add_types,
// Don't animate the first tab, it looks weird, and don't animate anything
// if the containing window isn't visible yet.
if (GetTabCount() > 1 && GetWidget() && GetWidget()->IsVisible()) {
pinned ? TabPinned::kPinned : TabPinned::kUnpinned);
} else {
model_index, tab, pinned ? TabPinned::kPinned : TabPinned::kUnpinned);
for (TabStripObserver& observer : observers_)
// Stop dragging when a new tab is added and dragging a window. Doing
// otherwise results in a confusing state if the user attempts to reattach. We
// could allow this and make TabDragController update itself during the add,
// but this comes up infrequently enough that it's not worth the complexity.
// At the start of AddTabAt() the model and tabs are out sync. Any queries to
// find a tab given a model index can go off the end of |tabs_|. As such, it
// is important that we complete the drag *after* adding the tab so that the
// model and tabstrip are in sync.
if (!drag_context_->IsMutating() && drag_context_->IsDraggingWindow())
Profile* profile = controller()->GetProfile();
if (profile) {
if (profile->IsGuestSession() || profile->IsEphemeralGuestProfile())
base::UmaHistogramCounts100("Tab.Count.Guest", GetTabCount());
else if (profile->IsIncognitoProfile())
base::UmaHistogramCounts100("Tab.Count.Incognito", GetTabCount());
void TabStrip::MoveTab(int from_model_index,
int to_model_index,
TabRendererData data) {
DCHECK_GT(tabs_.view_size(), 0);
Tab* moving_tab = tab_at(from_model_index);
const bool pinned = data.pinned;
GetViewInsertionIndex(moving_tab, from_model_index, to_model_index));
if (touch_layout_) {
tabs_.MoveViewOnly(from_model_index, to_model_index);
int pinned_count = 0;
const int start_x = UpdateIdealBoundsForPinnedTabs(&pinned_count);
touch_layout_->MoveTab(from_model_index, to_model_index,
controller_->GetActiveIndex(), start_x,
} else {
tabs_.Move(from_model_index, to_model_index);
selected_tabs_.Move(from_model_index, to_model_index, /*length=*/1);
layout_helper_->MoveTab(moving_tab->group(), from_model_index,
to_model_index, pinned ? TabPinned::kPinned : TabPinned::kUnpinned);
for (TabStripObserver& observer : observers_)
observer.OnTabMoved(from_model_index, to_model_index);
void TabStrip::RemoveTabAt(content::WebContents* contents,
int model_index,
bool was_active) {
StartRemoveTabAnimation(model_index, was_active);
for (TabStripObserver& observer : observers_)
// Stop dragging when a new tab is removed and dragging a window. Doing
// otherwise results in a confusing state if the user attempts to reattach. We
// could allow this and make TabDragController update itself during the
// remove operation, but this comes up infrequently enough that it's not worth
// the complexity.
// At the start of RemoveTabAt() the model and tabs are out sync. Any queries
// to find a tab given a model index can go off the end of |tabs_|. As such,
// it is important that we complete the drag *after* removing the tab so that
// the model and tabstrip are in sync.
if (!drag_context_->IsMutating() && drag_context_->IsDraggingTab(contents))
void TabStrip::SetTabData(int model_index, TabRendererData data) {
Tab* tab = tab_at(model_index);
const bool pinned = data.pinned;
const bool pinned_state_changed = tab->data().pinned != pinned;
if (HoverCardIsShowingForTab(tab))
if (pinned_state_changed) {
if (touch_layout_) {
int pinned_tab_count = 0;
int start_x = UpdateIdealBoundsForPinnedTabs(&pinned_tab_count);
touch_layout_->SetXAndPinnedCount(start_x, pinned_tab_count);
model_index, pinned ? TabPinned::kPinned : TabPinned::kUnpinned);
if (GetWidget() && GetWidget()->IsVisible())
void TabStrip::AddTabToGroup(base::Optional<tab_groups::TabGroupId> group,
int model_index) {
// Expand the group if the tab that is getting grouped is the active tab. This
// can result in the group expanding in a series of actions where the final
// active tab is not in the group.
if (model_index == && group.has_value() &&
controller()->IsGroupCollapsed(group.value())) {
group.value(), ToggleTabGroupCollapsedStateOrigin::kImplicitAction);
if (group.has_value())
void TabStrip::OnGroupCreated(const tab_groups::TabGroupId& group) {
auto group_view = std::make_unique<TabGroupViews>(this, group);
layout_helper_->InsertGroupHeader(group, group_view->header());
group_views_[group] = std::move(group_view);
void TabStrip::OnGroupEditorOpened(const tab_groups::TabGroupId& group) {
// The context menu relies on a Browser object which is not provided in
// TabStripTest.
if (this->controller()->GetBrowser()) {
this, gfx::Point(), ui::MENU_SOURCE_NONE);
void TabStrip::OnGroupContentsChanged(const tab_groups::TabGroupId& group) {
// The group header may be in the wrong place if the tab didn't actually
// move in terms of model indices.
void TabStrip::OnGroupVisualsChanged(const tab_groups::TabGroupId& group) {
// The group title may have changed size, so update bounds.
void TabStrip::ToggleTabGroup(const tab_groups::TabGroupId& group,
bool is_collapsing,
ToggleTabGroupCollapsedStateOrigin origin) {
if (is_collapsing && GetWidget()) {
in_tab_close_ = true;
if (origin == ToggleTabGroupCollapsedStateOrigin::kMouse) {
} else if (origin == ToggleTabGroupCollapsedStateOrigin::kGesture) {
} else {
// The current group header is expanded which is slightly smaller than the
// size when the header is collapsed. Calculate the size of the header once
// collapsed for maintaining its position. See
// TabGroupHeader::CalculateWidth() for more details.
const int empty_group_title_adjustment =
GetGroupTitle(group).empty() ? 2 : -2;
const int title_chip_width =
group_views_[group]->header()->GetTabSizeInfo().standard_width -
2 * TabStyle::GetTabOverlap() - empty_group_title_adjustment;
const int collapsed_header_width =
title_chip_width + 2 * TabGroupUnderline::GetStrokeInset();
override_available_width_for_tabs_ =
ideal_bounds(GetModelCount() - 1).right() -
group_views_[group]->GetBounds().width() + collapsed_header_width;
} else {
void TabStrip::OnGroupMoved(const tab_groups::TabGroupId& group) {
TabGroupHeader* group_header = group_views_[group]->header();
const int first_tab = controller_->GetFirstTabInGroup(group).value();
const int header_index = GetIndexOf(group_header);
const int first_tab_index = GetIndexOf(tab_at(first_tab));
// The header should be just before the first tab. If it isn't, reorder the
// header such that it is. Note that the index to reorder to is different
// depending on whether the header is before or after the tab, since the
// header itself occupies an index.
if (header_index < first_tab_index - 1)
ReorderChildView(group_header, first_tab_index - 1);
if (header_index > first_tab_index - 1)
ReorderChildView(group_header, first_tab_index);
void TabStrip::OnGroupClosed(const tab_groups::TabGroupId& group) {
void TabStrip::ShiftGroupLeft(const tab_groups::TabGroupId& group) {
ShiftGroupRelative(group, -1);
void TabStrip::ShiftGroupRight(const tab_groups::TabGroupId& group) {
ShiftGroupRelative(group, 1);
bool TabStrip::ShouldTabBeVisible(const Tab* tab) const {
// When the tabstrip is scrollable, it can grow to accommodate any number of
// tabs, so tabs can never become clipped.
// N.B. Tabs can still be not-visible because they're in a collapsed group,
// but that's handled elsewhere.
// N.B. This is separate from the tab being potentially scrolled offscreen -
// this solely determines whether the tab should be clipped for the
// pre-scrolling overflow behavior.
if (base::FeatureList::IsEnabled(features::kScrollableTabStrip))
return true;
// Detached tabs should always be invisible (as they close).
if (tab->detached())
return false;
// When stacking tabs, all tabs should always be visible.
if (stacked_layout_)
return true;
// If the tab would be clipped by the trailing edge of the strip, even if the
// tabstrip were resized to its greatest possible width, it shouldn't be
// visible.
const int right_edge = tab->bounds().right();
const int tabstrip_right = CalculateAvailableWidthForTabs();
if (right_edge > tabstrip_right)
return false;
// Non-clipped dragging tabs should always be visible.
if (tab->dragging())
return true;
// Let all non-clipped closing tabs be visible. These will probably finish
// closing before the user changes the active tab, so there's little reason to
// try and make the more complex logic below apply.
if (tab->closing())
return true;
// Now we need to check whether the tab isn't currently clipped, but could
// become clipped if we changed the active tab, widening either this tab or
// the tabstrip portion before it.
// Pinned tabs don't change size when activated, so any tab in the pinned tab
// region is safe.
if (tab->data().pinned)
return true;
// If the active tab is on or before this tab, we're safe.
if (controller_->GetActiveIndex() <= GetModelIndexOf(tab))
return true;
// We need to check what would happen if the active tab were to move to this
// tab or before.
return (right_edge + GetActiveTabWidth() - GetInactiveTabWidth()) <=
bool TabStrip::ShouldDrawStrokes() const {
// If the controller says we can't draw strokes, don't.
if (!controller_->CanDrawStrokes())
return false;
// The tabstrip normally avoids strokes and relies on the active tab
// contrasting sufficiently with the frame background. When there isn't
// enough contrast, fall back to a stroke. Always compute the contrast ratio
// against the active frame color, to avoid toggling the stroke on and off as
// the window activation state changes.
constexpr float kMinimumContrastRatioForOutlines = 1.3f;
const SkColor background_color = GetTabBackgroundColor(
TabActive::kActive, BrowserFrameActiveState::kActive);
const SkColor frame_color =
const float contrast_ratio =
color_utils::GetContrastRatio(background_color, frame_color);
if (contrast_ratio < kMinimumContrastRatioForOutlines)
return true;
// Don't want to have to run a full feature query every time this function is
// called.
static const bool tab_outlines_in_low_contrast =
if (tab_outlines_in_low_contrast) {
constexpr float kMinimumAbsoluteContrastForOutlines = 0.2f;
const float background_luminance =
const float frame_luminance =
const float contrast_difference =
std::fabs(background_luminance - frame_luminance);
if (contrast_difference < kMinimumAbsoluteContrastForOutlines)
return true;
return false;
void TabStrip::SetSelection(const ui::ListSelectionModel& new_selection) {
<< "We should never transition to a state where no tab is active.";
Tab* const new_active_tab = tab_at(;
Tab* const old_active_tab = >= 0 ? tab_at( : nullptr;
if (new_active_tab != old_active_tab) {
if (old_active_tab) {
if (old_active_tab->group().has_value())
if (new_active_tab->group().has_value()) {
const tab_groups::TabGroupId new_group = new_active_tab->group().value();
// If the tab that is about to be activated is in a collapsed group,
// automatically expand the group.
if (controller()->IsGroupCollapsed(new_group))
new_group, ToggleTabGroupCollapsedStateOrigin::kImplicitAction);
if (touch_layout_) {
// Only start an animation if we need to. Otherwise clicking on an
// unselected tab and dragging won't work because dragging is only allowed
// if not animating.
if (!views::ViewModelUtils::IsAtIdealBounds(tabs_))
} else {
if (GetActiveTabWidth() == GetInactiveTabWidth()) {
// When tabs are wide enough, selecting a new tab cannot change the
// ideal bounds, so only a repaint is necessary.
} else if (IsAnimating()) {
// The selection change will have modified the ideal bounds of the tabs
// in |selected_tabs_| and |new_selection|. We need to recompute.
// Note: This is safe even if we're in the midst of mouse-based tab
// closure--we won't expand the tabstrip back to the full window
// width--because PrepareForCloseAt() will have set
// |override_available_width_for_tabs_| already.
} else {
// As in the animating case above, the selection change will have
// affected the desired bounds of the tabs, but since we're not animating
// we can just snap to the new bounds.
// Use STLSetDifference to get the indices of elements newly selected
// and no longer selected, since selected_indices() is always sorted.
ui::ListSelectionModel::SelectedIndices no_longer_selected =
selected_tabs_.selected_indices(), new_selection.selected_indices());
ui::ListSelectionModel::SelectedIndices newly_selected =
new_selection.selected_indices(), selected_tabs_.selected_indices());
new_active_tab->NotifyAccessibilityEvent(ax::mojom::Event::kSelection, true);
selected_tabs_ = new_selection;
// The hover cards seen count is reset when the active tab is changed by any
// event. Note TabStrip::SelectTab does not capture tab changes triggered by
// the keyboard.
if (base::FeatureList::IsEnabled(features::kTabHoverCards) && hover_card_)
// Notify all tabs whose selected state changed.
for (auto tab_index :
no_longer_selected, newly_selected)) {
void TabStrip::OnWidgetActivationChanged(views::Widget* widget, bool active) {
if (active && >= 0) {
// When the browser window is activated, fire a selection event on the
// currently active tab, to help enable per-tab modes in assistive
// technologies.
->NotifyAccessibilityEvent(ax::mojom::Event::kSelection, true);
void TabStrip::SetTabNeedsAttention(int model_index, bool attention) {
const gfx::Rect& TabStrip::ideal_bounds(tab_groups::TabGroupId group) const {
return layout_helper_->group_header_ideal_bounds().at(group);
int TabStrip::GetModelIndexOf(const TabSlotView* view) const {
return tabs_.GetIndexOfView(view);
int TabStrip::GetTabCount() const {
return tabs_.view_size();
int TabStrip::GetModelCount() const {
return controller_->GetCount();
bool TabStrip::IsValidModelIndex(int model_index) const {
return controller_->IsValidIndex(model_index);
TabDragContext* TabStrip::GetDragContext() {
return drag_context_.get();
int TabStrip::GetPinnedTabCount() const {
return layout_helper_->GetPinnedTabCount();
bool TabStrip::IsAnimating() const {
return bounds_animator_.IsAnimating();
void TabStrip::StopAnimating(bool layout) {
if (!IsAnimating())
if (layout)
base::Optional<int> TabStrip::GetFocusedTabIndex() const {
for (int i = 0; i < tabs_.view_size(); ++i) {
if (tabs_.view_at(i)->HasFocus())
return i;
return base::nullopt;
views::View* TabStrip::GetTabViewForPromoAnchor(int index_hint) {
return tab_at(base::ClampToRange(index_hint, 0, GetTabCount() - 1));
views::View* TabStrip::GetDefaultFocusableChild() {
int active = controller_->GetActiveIndex();
return active != TabStripModel::kNoTab ? tab_at(active) : nullptr;
const ui::ListSelectionModel& TabStrip::GetSelectionModel() const {
return controller_->GetSelectionModel();
bool TabStrip::SupportsMultipleSelection() {
// Currently we only allow single selection in touch layout mode.
return touch_layout_ == nullptr;
bool TabStrip::ShouldHideCloseButtonForTab(Tab* tab) const {
if (tab->IsActive())
return false;
return !!touch_layout_;
void TabStrip::SelectTab(Tab* tab, const ui::Event& event) {
int model_index = GetModelIndexOf(tab);
if (IsValidModelIndex(model_index)) {
if (!tab->IsActive()) {
int current_selection =;
current_selection - model_index);
GetModelCount() - model_index - 1);
if (tab->group().has_value()) {
// Report histogram metrics for the number of tab hover cards seen before
// a tab is selected by mouse press.
if (base::FeatureList::IsEnabled(features::kTabHoverCards) && hover_card_ &&
event.type() == ui::ET_MOUSE_PRESSED && !tab->IsActive()) {
controller_->SelectTab(model_index, event);
void TabStrip::ExtendSelectionTo(Tab* tab) {
int model_index = GetModelIndexOf(tab);
if (IsValidModelIndex(model_index))
void TabStrip::ToggleSelected(Tab* tab) {
int model_index = GetModelIndexOf(tab);
if (IsValidModelIndex(model_index))
void TabStrip::AddSelectionFromAnchorTo(Tab* tab) {
int model_index = GetModelIndexOf(tab);
if (IsValidModelIndex(model_index))
void TabStrip::CloseTab(Tab* tab, CloseTabSource source) {
if (tab->closing()) {
// If the tab is already closing, close the next tab. We do this so that the
// user can rapidly close tabs by clicking the close button and not have
// the animations interfere with that.
std::vector<Tab*> all_tabs = layout_helper_->GetTabs();
auto it = std::find(all_tabs.begin(), all_tabs.end(), tab);
while (it < all_tabs.end() && (*it)->closing()) {
if (it == all_tabs.end())
tab = *it;
CloseTabInternal(GetModelIndexOf(tab), source);
void TabStrip::ShiftTabNext(Tab* tab) {
ShiftTabRelative(tab, 1);
void TabStrip::ShiftTabPrevious(Tab* tab) {
ShiftTabRelative(tab, -1);
void TabStrip::MoveTabFirst(Tab* tab) {
if (tab->closing())
const int start_index = GetModelIndexOf(tab);
if (!IsValidModelIndex(start_index))
int target_index = 0;
if (!controller_->IsTabPinned(start_index)) {
while (target_index < start_index && controller_->IsTabPinned(target_index))
if (!IsValidModelIndex(target_index))
if (target_index != start_index)
controller_->MoveTab(start_index, target_index);
// The tab may unintentionally land in the first group in the tab strip, so we
// remove the group to ensure consistent behavior. Even if the tab is already
// at the front, it should "move" out of its current group.
if (tab->group().has_value())
void TabStrip::MoveTabLast(Tab* tab) {
if (tab->closing())
const int start_index = GetModelIndexOf(tab);
if (!IsValidModelIndex(start_index))
int target_index;
if (controller_->IsTabPinned(start_index)) {
int temp_index = start_index + 1;
while (temp_index < GetTabCount() && controller_->IsTabPinned(temp_index))
target_index = temp_index - 1;
} else {
target_index = GetTabCount() - 1;
if (!IsValidModelIndex(target_index))
if (target_index != start_index)
controller_->MoveTab(start_index, target_index);
// The tab may unintentionally land in the last group in the tab strip, so we
// remove the group to ensure consistent behavior. Even if the tab is already
// at the back, it should "move" out of its current group.
if (tab->group().has_value())
void TabStrip::ShowContextMenuForTab(Tab* tab,
const gfx::Point& p,
ui::MenuSourceType source_type) {
controller_->ShowContextMenuForTab(tab, p, source_type);
bool TabStrip::IsActiveTab(const Tab* tab) const {
int model_index = GetModelIndexOf(tab);
return IsValidModelIndex(model_index) &&
bool TabStrip::IsTabSelected(const Tab* tab) const {
int model_index = GetModelIndexOf(tab);
return IsValidModelIndex(model_index) &&
bool TabStrip::IsTabPinned(const Tab* tab) const {
if (tab->closing())
return false;
int model_index = GetModelIndexOf(tab);
return IsValidModelIndex(model_index) &&
bool TabStrip::IsTabFirst(const Tab* tab) const {
return GetModelIndexOf(tab) == 0;
bool TabStrip::IsFocusInTabs() const {
return GetFocusManager() && Contains(GetFocusManager()->GetFocusedView());
void TabStrip::MaybeStartDrag(
TabSlotView* source,
const ui::LocatedEvent& event,
const ui::ListSelectionModel& original_selection) {
// Don't accidentally start any drag operations during animations if the
// mouse is down... during an animation tabs are being resized automatically,
// so the View system can misinterpret this easily if the mouse is down that
// the user is dragging.
if (IsAnimating() || controller_->HasAvailableDragActions() == 0)
// Check that the source is either a valid tab or a tab group header, which
// are the only valid drag targets.
if (!IsValidModelIndex(GetModelIndexOf(source))) {
drag_context_->MaybeStartDrag(source, event, original_selection);
void TabStrip::ContinueDrag(views::View* view, const ui::LocatedEvent& event) {
drag_context_->ContinueDrag(view, event);
bool TabStrip::EndDrag(EndDragReason reason) {
return drag_context_->EndDrag(reason);
Tab* TabStrip::GetTabAt(const gfx::Point& point) {
views::View* view = GetEventHandlerForPoint(point);
if (!view)
return nullptr; // No tab contains the point.
// Walk up the view hierarchy until we find a tab, or the TabStrip.
while (view && view != this && view->GetID() != VIEW_ID_TAB)
view = view->parent();
return view && view->GetID() == VIEW_ID_TAB ? static_cast<Tab*>(view)
: nullptr;
const Tab* TabStrip::GetAdjacentTab(const Tab* tab, int offset) {
int index = GetModelIndexOf(tab);
if (index < 0)
return nullptr;
index += offset;
return IsValidModelIndex(index) ? tab_at(index) : nullptr;
void TabStrip::OnMouseEventInTab(views::View* source,
const ui::MouseEvent& event) {
// Record time from cursor entering the tabstrip to first tap on a tab to
// switch.
if (mouse_entered_tabstrip_time_.has_value() &&
event.type() == ui::ET_MOUSE_PRESSED && views::IsViewClass<Tab>(source)) {
base::TimeTicks::Now() - mouse_entered_tabstrip_time_.value());
UpdateStackedLayoutFromMouseEvent(source, event);
void TabStrip::UpdateHoverCard(Tab* tab) {
if (!base::FeatureList::IsEnabled(features::kTabHoverCards))
// We don't want to show a hover card while the tabstrip is animating.
if (bounds_animator_.IsAnimating()) {
if (!hover_card_) {
// There is nothing to be done if the hover card doesn't exist and we are
// not trying to show it.
if (!tab)
hover_card_ = new TabHoverCardBubbleView(tab);
if (GetWidget()) {
hover_card_event_sniffer_ =
std::make_unique<TabHoverCardEventSniffer>(hover_card_, this);
if (tab)
bool TabStrip::ShowDomainInHoverCards() const {
const auto* app_controller = controller_->GetBrowser()->app_controller();
return !app_controller || !app_controller->is_for_system_web_app();
bool TabStrip::HoverCardIsShowingForTab(Tab* tab) {
if (!base::FeatureList::IsEnabled(features::kTabHoverCards))
return false;
return hover_card_ && hover_card_->GetWidget()->IsVisible() &&
!hover_card_->IsFadingOut() &&
hover_card_->GetDesiredAnchorView() == tab;
int TabStrip::GetBackgroundOffset() const {
return background_offset_;
int TabStrip::GetStrokeThickness() const {
return ShouldDrawStrokes() ? 1 : 0;
bool TabStrip::CanPaintThrobberToLayer() const {
// Disable layer-painting of throbbers if dragging, if any tab animation is in
// progress, or if stacked tabs are enabled. Also disable in fullscreen: when
// "immersive" the tab strip could be sliding in or out; for other modes,
// there's no tab strip.
const bool dragging = drag_context_->IsDragStarted();
const views::Widget* widget = GetWidget();
return widget && !touch_layout_ && !dragging && !IsAnimating() &&
bool TabStrip::HasVisibleBackgroundTabShapes() const {
return controller_->HasVisibleBackgroundTabShapes();
bool TabStrip::ShouldPaintAsActiveFrame() const {
return controller_->ShouldPaintAsActiveFrame();
SkColor TabStrip::GetToolbarTopSeparatorColor() const {
return controller_->GetToolbarTopSeparatorColor();
SkColor TabStrip::GetTabSeparatorColor() const {
return separator_color_;
SkColor TabStrip::GetTabBackgroundColor(
TabActive active,
BrowserFrameActiveState active_state) const {
const ui::ThemeProvider* tp = GetThemeProvider();
if (!tp)
return SK_ColorBLACK;
constexpr int kColorIds[2][2] = {
using State = BrowserFrameActiveState;
const bool tab_active = active == TabActive::kActive;
const bool frame_active =
(active_state == State::kActive) ||
((active_state == State::kUseCurrent) && ShouldPaintAsActiveFrame());
return tp->GetColor(kColorIds[tab_active][frame_active]);
SkColor TabStrip::GetTabForegroundColor(TabActive active,
SkColor background_color) const {
const ui::ThemeProvider* tp = GetThemeProvider();
if (!tp)
return SK_ColorBLACK;
constexpr int kColorIds[2][2] = {
const bool tab_active = active == TabActive::kActive;
const bool frame_active = ShouldPaintAsActiveFrame();
const int color_id = kColorIds[tab_active][frame_active];
SkColor color = tp->GetColor(color_id);
if (tp->HasCustomColor(color_id))
return color;
if ((color_id ==
// If a custom theme sets a background tab text color for active but not
// inactive windows, generate the inactive color by blending the active one
// at 75% as we do in the default theme.
color = tp->GetColor(
if (!frame_active)
color = color_utils::AlphaBlend(color, background_color, 0.75f);
// To minimize any readability cost of custom system frame colors, try to make
// the text reach the same contrast ratio that it would in the default theme.
const SkColor target = color_utils::GetColorWithMaxContrast(background_color);
// These contrast ratios should match the actual ratios in the default theme
// colors when no system colors are involved, except for the inactive tab/
// inactive frame case, which has been raised from 4.48 to 4.5 to meet
// accessibility guidelines.
constexpr float kContrast[2][2] = {{4.5f, // Inactive tab, inactive frame
7.98f}, // Inactive tab, active frame
{5.0f, // Active tab, inactive frame
10.46f}}; // Active tab, active frame
const float contrast = kContrast[tab_active][frame_active];
return color_utils::BlendForMinContrast(color, background_color, target,
// Returns the accessible tab name for the tab.
base::string16 TabStrip::GetAccessibleTabName(const Tab* tab) const {
const int model_index = GetModelIndexOf(tab);
return IsValidModelIndex(model_index) ? controller_->GetAccessibleTabName(tab)
: base::string16();
base::Optional<int> TabStrip::GetCustomBackgroundId(
BrowserFrameActiveState active_state) const {
if (!TitlebarBackgroundIsTransparent())
return controller_->GetCustomBackgroundId(active_state);
constexpr int kBackgroundIdGlass = IDR_THEME_TAB_BACKGROUND_V;
return GetThemeProvider()->HasCustomImage(kBackgroundIdGlass)
? base::make_optional(kBackgroundIdGlass)
: base::nullopt;
gfx::Rect TabStrip::GetTabAnimationTargetBounds(const Tab* tab) {
return bounds_animator_.GetTargetBounds(tab);
void TabStrip::MouseMovedOutOfHost() {
if (reset_to_shrink_on_exit_) {
reset_to_shrink_on_exit_ = false;
float TabStrip::GetHoverOpacityForTab(float range_parameter) const {
return gfx::Tween::FloatValueBetween(range_parameter, hover_opacity_min_,
float TabStrip::GetHoverOpacityForRadialHighlight() const {
return radial_highlight_opacity_;
base::string16 TabStrip::GetGroupTitle(
const tab_groups::TabGroupId& group) const {
return controller_->GetGroupTitle(group);
tab_groups::TabGroupColorId TabStrip::GetGroupColorId(
const tab_groups::TabGroupId& group) const {
return controller_->GetGroupColorId(group);
SkColor TabStrip::GetPaintedGroupColor(
const tab_groups::TabGroupColorId& color_id) const {
return GetThemeProvider()->GetColor(
GetTabGroupTabStripColorId(color_id, ShouldPaintAsActiveFrame()));
// TabStrip, views::AccessiblePaneView overrides:
void TabStrip::Layout() {
if (IsAnimating()) {
// Hide tabs that have animated at least partially out of the clip region.
if (base::FeatureList::IsEnabled(features::kScrollableTabStrip)) {
// With tab scrolling, the tabstrip is solely responsible for its own
// width.
// It should never be larger than its preferred width.
const int max_width = CalculatePreferredSize().width();
// It should never be smaller than its minimum width.
const int min_width = GetMinimumSize().width();
// If it can, it should fit within the tab strip region.
const int available_width = available_width_callback_.Run();
// It should be as wide as possible subject to the above constraints.
const int width = std::min(max_width, std::max(min_width, available_width));
SetBounds(0, 0, width, GetLayoutConstant(TAB_HEIGHT));
// Only do a layout if our size or the available width changed.
const int available_width = GetAvailableWidthForTabStrip();
if (last_layout_size_ == size() && last_available_width_ == available_width)
if (drag_context_->IsDragSessionActive())
void TabStrip::PaintChildren(const views::PaintInfo& paint_info) {
// This is used to log to UMA. NO EARLY RETURNS!
base::ElapsedTimer paint_timer;
// The view order doesn't match the paint order (layout_helper_ contains the
// view ordering).
bool is_dragging = false;
Tab* active_tab = nullptr;
std::vector<Tab*> tabs_dragging;
std::vector<Tab*> selected_and_hovered_tabs;
// When background tab shapes are visible, as for hovered or selected tabs,
// the paint order must be handled carefully to avoid Z-order errors, so
// this code defers drawing such tabs until later.
const auto paint_or_add_to_tabs = [&paint_info,
&selected_and_hovered_tabs](Tab* tab) {
if (tab->tab_style()->GetZValue() > 0.0) {
} else {
std::vector<Tab*> all_tabs = layout_helper_->GetTabs();
int active_tab_index = -1;
for (int i = all_tabs.size() - 1; i >= 0; --i) {
Tab* tab = all_tabs[i];
if (tab->dragging() && !stacked_layout_) {
is_dragging = true;
if (tab->IsActive()) {
active_tab = tab;
active_tab_index = i;
} else {
} else if (tab->IsActive()) {
active_tab = tab;
active_tab_index = i;
} else if (!stacked_layout_) {
// Draw from the left and then the right if we're in touch mode.
if (stacked_layout_ && active_tab_index >= 0) {
for (int i = 0; i < active_tab_index; ++i) {
Tab* tab = all_tabs[i];
for (int i = all_tabs.size() - 1; i > active_tab_index; --i) {
Tab* tab = all_tabs[i];
selected_and_hovered_tabs.end(), [](Tab* tab1, Tab* tab2) {
return tab1->tab_style()->GetZValue() <
for (Tab* tab : selected_and_hovered_tabs)
// Keep track of the dragging group if dragging by the group header, or
// the current group if just dragging tabs into a group. At most one of these
// will have a value, since a drag is either a group drag or a tab drag.
base::Optional<tab_groups::TabGroupId> dragging_group = base::nullopt;
base::Optional<tab_groups::TabGroupId> current_group = base::nullopt;
// Paint group headers and underlines.
for (const auto& group_view_pair : group_views_) {
if (group_view_pair.second->header()->dragging()) {
// If the whole group is dragging, defer painting both the header and the
// underline, since they should appear above non-dragging tabs and groups.
// Instead, just track the dragging group.
dragging_group = group_view_pair.first;
} else {
if (tabs_dragging.size() > 0 &&
tabs_dragging[0]->group() == group_view_pair.first) {
// If tabs are being dragged into a group, defer painting just the
// underline, which should appear above non-active dragging tabs as well
// as all non-dragging tabs and groups. Instead, just track the group
// that the tabs are being dragged into.
current_group = group_view_pair.first;
} else {
// Always paint the active tab over all the inactive tabs.
if (active_tab && !is_dragging)
// If dragging a group, paint the group highlight and header above all
// non-dragging tabs and groups.
if (dragging_group.has_value()) {
// Paint the dragged tabs.
for (size_t i = 0; i < tabs_dragging.size(); ++i)
// If dragging a group, or dragging tabs into a group, paint the group
// underline above the dragging tabs. Otherwise, any non-active dragging tabs
// will not get an underline.
if (dragging_group.has_value())
if (current_group.has_value())
// If the active tab is being dragged, it goes last.
if (active_tab && is_dragging)
"TabStrip.PaintChildrenDuration", paint_timer.Elapsed(),
base::TimeDelta::FromMicroseconds(10000), 50);
gfx::Size TabStrip::GetMinimumSize() const {
// If tabs can be stacked, our minimum width is the smallest width of the
// stacked tabstrip.
const int minimum_width =
(touch_layout_ || adjust_layout_)
? GetStackableTabWidth() + (2 * kStackedPadding * kMaxStackedCount)
: layout_helper_->CalculateMinimumWidth();
return gfx::Size(minimum_width, GetLayoutConstant(TAB_HEIGHT));
gfx::Size TabStrip::CalculatePreferredSize() const {
int preferred_width;
// The tabstrip needs to always exactly fit the bounds of the tabs so that
// NTB can be laid out just to the right of the rightmost tab. When the tabs
// aren't at their ideal bounds (i.e. during animation or a drag), we need to
// size ourselves to exactly fit wherever the tabs *currently* are.
if (IsAnimating() || drag_context_->IsDragSessionActive()) {
// The visual order of the tabs can be out of sync with the logical order,
// so we have to check all of them to find the visually trailing-most one.
int max_x = 0;
for (auto* tab : layout_helper_->GetTabs()) {
max_x = std::max(max_x, tab->bounds().right());
// The tabs span from 0 to |max_x|, so |max_x| is the current width
// occupied by tabs. We report the current width as our preferred width so
// that the tab strip is sized to exactly fit the current position of the
// tabs.
preferred_width = max_x;
} else {
preferred_width = override_available_width_for_tabs_
? override_available_width_for_tabs_.value()
: layout_helper_->CalculatePreferredWidth();
return gfx::Size(preferred_width, GetLayoutConstant(TAB_HEIGHT));
views::View* TabStrip::GetTooltipHandlerForPoint(const gfx::Point& point) {
if (!HitTestPoint(point))
return nullptr;
if (!touch_layout_) {
// Return any view that isn't a Tab or this TabStrip immediately. We don't
// want to interfere.
views::View* v = View::GetTooltipHandlerForPoint(point);
if (v && v != this && !views::IsViewClass<Tab>(v))
return v;
views::View* tab = FindTabHitByPoint(point);
if (tab)
return tab;
} else {
Tab* tab = FindTabForEvent(point);
if (tab)
return ConvertPointToViewAndGetTooltipHandler(this, tab, point);
return this;
BrowserRootView::DropIndex TabStrip::GetDropIndex(
const ui::DropTargetEvent& event) {
// Force animations to stop, otherwise it makes the index calculation tricky.
// If the UI layout is right-to-left, we need to mirror the mouse
// coordinates since we calculate the drop index based on the
// original (and therefore non-mirrored) positions of the tabs.
const int x = GetMirroredXInView(event.x());
for (int i = 0; i < GetTabCount(); ++i) {
Tab* tab = tab_at(i);
const int tab_max_x = tab->x() + tab->width();
// When hovering over the left or right quarter of a tab, the drop indicator
// will point between tabs.
const int hot_width = tab->width() / 4;
if (x < tab_max_x) {
if (x >= (tab_max_x - hot_width))
return {i + 1, true};
return {i, x < tab->x() + hot_width};
// The drop isn't over a tab, add it to the end.
return {GetTabCount(), true};
views::View* TabStrip::GetViewForDrop() {
return this;
void TabStrip::HandleDragUpdate(
const base::Optional<BrowserRootView::DropIndex>& index) {
void TabStrip::HandleDragExited() {
// TabStrip, private:
void TabStrip::Init() {
// So we get enter/exit on children to switch stacked layout on and off.
if (g_drop_indicator_width == 0) {
// Direction doesn't matter, both images are the same size.
gfx::ImageSkia* drop_image = GetDropArrowImage(true);
g_drop_indicator_width = drop_image->width();
g_drop_indicator_height = drop_image->height();
if (!gfx::Animation::ShouldRenderRichAnimation())
std::map<tab_groups::TabGroupId, TabGroupHeader*> TabStrip::GetGroupHeaders() {
std::map<tab_groups::TabGroupId, TabGroupHeader*> group_headers;
for (const auto& group_view_pair : group_views_) {
return group_headers;
void TabStrip::NewTabButtonPressed(const ui::Event& event) {
if (event.IsMouseEvent()) {
// Prevent the hover card from popping back in immediately. This forces a
// normal fade-in.
if (hover_card_)
const ui::MouseEvent& mouse = static_cast<const ui::MouseEvent&>(event);
if (mouse.IsOnlyMiddleMouseButton()) {
if (ui::Clipboard::IsSupportedClipboardBuffer(
ui::ClipboardBuffer::kSelection)) {
ui::Clipboard* clipboard = ui::Clipboard::GetForCurrentThread();
base::string16 clipboard_text;
/* data_dst = */ nullptr, &clipboard_text);
if (!clipboard_text.empty())
if (event.type() == ui::ET_GESTURE_TAP)
void TabStrip::StartInsertTabAnimation(int model_index, TabPinned pinned) {
layout_helper_->InsertTabAt(model_index, tab_at(model_index), pinned);
gfx::Rect bounds = tab_at(model_index)->bounds();
// Adjust the starting bounds of the new tab.
const int tab_overlap = TabStyle::GetTabOverlap();
if (model_index > 0) {
// If we have a tab to our left, start at its right edge.
bounds.set_x(tab_at(model_index - 1)->bounds().right() - tab_overlap);
} else if (model_index + 1 < GetTabCount()) {
// Otherwise, if we have a tab to our right, start at its left edge.
bounds.set_x(tab_at(model_index + 1)->bounds().x());
} else {
NOTREACHED() << "First tab inserted into the tabstrip should not animate.";
// Start at the width of the overlap in order to animate at the same speed
// the surrounding tabs are moving, since at this width the subsequent tab
// is naturally positioned at the same X coordinate.
// Animate in to the full width.
void TabStrip::StartRemoveTabAnimation(int model_index, bool was_active) {
const int model_count = GetModelCount();
const int tab_overlap = TabStyle::GetTabOverlap();
if (in_tab_close_ && model_count > 0 && model_index != model_count) {
// The user closed a tab other than the last tab. Set
// override_available_width_for_tabs_ so that as the user closes tabs with
// the mouse a tab continues to fall under the mouse.
int next_active_index = controller_->GetActiveIndex();
if (model_index <= next_active_index) {
// At this point, model's internal state has already been updated.
// |contents| has been detached from model and the active index has been
// updated. But the tab for |contents| isn't removed yet. Thus, we need to
// fix up next_active_index based on it.
Tab* next_active_tab = tab_at(next_active_index);