views/view.cc

// Copyright (c) 2011 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 "views/view.h"

#include <algorithm>

#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "base/message_loop.h"
#include "base/utf_string_conversions.h"
#include "third_party/skia/include/core/SkRect.h"
#include "ui/base/accessibility/accessibility_types.h"
#include "ui/base/dragdrop/drag_drop_types.h"
#include "ui/gfx/canvas_skia.h"
#include "ui/gfx/compositor/compositor.h"
#include "ui/gfx/compositor/layer.h"
#include "ui/gfx/path.h"
#include "ui/gfx/point3.h"
#include "ui/gfx/transform.h"
#include "views/background.h"
#include "views/context_menu_controller.h"
#include "views/drag_controller.h"
#include "views/layer_property_setter.h"
#include "views/layout/layout_manager.h"
#include "views/views_delegate.h"
#include "views/widget/native_widget_private.h"
#include "views/widget/native_widget_views.h"
#include "views/widget/root_view.h"
#include "views/widget/tooltip_manager.h"
#include "views/widget/widget.h"

#if defined(OS_WIN)
#include "base/win/scoped_gdi_object.h"
#include "views/accessibility/native_view_accessibility_win.h"
#endif
#if defined(OS_LINUX)
#include "ui/base/gtk/scoped_handle_gtk.h"
#endif

namespace {

// Whether to use accelerated compositing when necessary (e.g. when a view has a
// transformation).
#if !defined(OS_CHROMEOS) || defined(TOUCH_UI)
bool use_acceleration_when_possible = true;
#else
bool use_acceleration_when_possible = false;
#endif

// Saves the drawing state, and restores the state when going out of scope.
class ScopedCanvas {
 public:
  explicit ScopedCanvas(gfx::Canvas* canvas) : canvas_(canvas) {
    if (canvas_)
      canvas_->Save();
  }
  ~ScopedCanvas() {
    if (canvas_)
      canvas_->Restore();
  }
  void SetCanvas(gfx::Canvas* canvas) {
    if (canvas_)
      canvas_->Restore();
    canvas_ = canvas;
    canvas_->Save();
  }

 private:
  gfx::Canvas* canvas_;

  DISALLOW_COPY_AND_ASSIGN(ScopedCanvas);
};

}  // namespace

namespace views {

// static
ViewsDelegate* ViewsDelegate::views_delegate = NULL;

// static
char View::kViewClassName[] = "views/View";

////////////////////////////////////////////////////////////////////////////////
// View, public:

// TO BE MOVED -----------------------------------------------------------------

void View::SetHotTracked(bool flag) {
}

bool View::IsHotTracked() const {
  return false;
}

// Creation and lifetime -------------------------------------------------------

View::View()
    : parent_owned_(true),
      id_(0),
      group_(-1),
      parent_(NULL),
      visible_(true),
      enabled_(true),
      registered_for_visible_bounds_notification_(false),
      clip_x_(0.0),
      clip_y_(0.0),
      needs_layout_(true),
      flip_canvas_on_paint_for_rtl_ui_(false),
      accelerator_registration_delayed_(false),
      accelerator_focus_manager_(NULL),
      registered_accelerator_count_(0),
      next_focusable_view_(NULL),
      previous_focusable_view_(NULL),
      focusable_(false),
      accessibility_focusable_(false),
      context_menu_controller_(NULL),
      drag_controller_(NULL) {
}

View::~View() {
  if (parent_)
    parent_->RemoveChildView(this);

  for (Views::const_iterator i(children_.begin()); i != children_.end(); ++i) {
    (*i)->parent_ = NULL;
    if ((*i)->parent_owned())
      delete *i;
  }

#if defined(OS_WIN)
  if (native_view_accessibility_win_.get())
    native_view_accessibility_win_->set_view(NULL);
#endif
}

// Tree operations -------------------------------------------------------------

const Widget* View::GetWidget() const {
  // The root view holds a reference to this view hierarchy's Widget.
  return parent_ ? parent_->GetWidget() : NULL;
}

Widget* View::GetWidget() {
  return const_cast<Widget*>(const_cast<const View*>(this)->GetWidget());
}

void View::AddChildView(View* view) {
  AddChildViewAt(view, child_count());
}

void View::AddChildViewAt(View* view, int index) {
  CHECK_NE(view, this) << "You cannot add a view as its own child";

  // If |view| has a parent, remove it from its parent.
  View* parent = view->parent_;
  if (parent)
    parent->RemoveChildView(view);

  // Sets the prev/next focus views.
  InitFocusSiblings(view, index);

  // Let's insert the view.
  view->parent_ = this;
  children_.insert(children_.begin() + index, view);

  if (GetWidget()) {
    // Sending out notification of insert may result in adding other views.
    // Invoke this first to make sure we know the layer is created (if needed).
    view->CreateLayerIfNecessary();
  }

  for (View* v = this; v; v = v->parent_)
    v->ViewHierarchyChangedImpl(false, true, this, view);

  view->PropagateAddNotifications(this, view);
  UpdateTooltip();
  if (GetWidget()) {
    RegisterChildrenForVisibleBoundsNotification(view);
    view->CreateLayerIfNecessary();
  }

  if (layout_manager_.get())
    layout_manager_->ViewAdded(this, view);

  view->MarkLayerDirty();
}

void View::ReorderChildView(View* view, int index) {
  DCHECK_EQ(view->parent_, this);
  if (index < 0)
    index = child_count() - 1;
  else if (index >= child_count())
    return;
  if (children_[index] == view)
    return;

  const Views::iterator i(std::find(children_.begin(), children_.end(), view));
  DCHECK(i != children_.end());
  children_.erase(i);

  // Unlink the view first
  View* next_focusable = view->next_focusable_view_;
  View* prev_focusable = view->previous_focusable_view_;
  if (prev_focusable)
    prev_focusable->next_focusable_view_ = next_focusable;
  if (next_focusable)
    next_focusable->previous_focusable_view_ = prev_focusable;

  // Add it in the specified index now.
  InitFocusSiblings(view, index);
  children_.insert(children_.begin() + index, view);
}

void View::RemoveChildView(View* view) {
  DoRemoveChildView(view, true, true, false);
}

void View::RemoveAllChildViews(bool delete_children) {
  while (!children_.empty())
    DoRemoveChildView(children_.front(), false, false, delete_children);
  UpdateTooltip();
}

bool View::Contains(const View* view) const {
  for (const View* v = view; v; v = v->parent_) {
    if (v == this)
      return true;
  }
  return false;
}

int View::GetIndexOf(const View* view) const {
  Views::const_iterator i(std::find(children_.begin(), children_.end(), view));
  return i != children_.end() ? static_cast<int>(i - children_.begin()) : -1;
}

// Size and disposition --------------------------------------------------------

void View::SetBounds(int x, int y, int width, int height) {
  SetBoundsRect(gfx::Rect(x, y, std::max(0, width), std::max(0, height)));
}

void View::SetBoundsRect(const gfx::Rect& bounds) {
  if (bounds == bounds_) {
    if (needs_layout_) {
      needs_layout_ = false;
      Layout();
      SchedulePaint();
    }
    return;
  }

  if (IsVisible()) {
    // Paint where the view is currently.
    SchedulePaintBoundsChanged(
        bounds_.size() == bounds.size() ? SCHEDULE_PAINT_SIZE_SAME :
        SCHEDULE_PAINT_SIZE_CHANGED);
  }

  gfx::Rect prev = bounds_;
  bounds_ = bounds;
  BoundsChanged(prev);
}

void View::SetSize(const gfx::Size& size) {
  SetBounds(x(), y(), size.width(), size.height());
}

void View::SetPosition(const gfx::Point& position) {
  SetBounds(position.x(), position.y(), width(), height());
}

void View::SetX(int x) {
  SetBounds(x, y(), width(), height());
}

void View::SetY(int y) {
  SetBounds(x(), y, width(), height());
}

gfx::Rect View::GetContentsBounds() const {
  gfx::Rect contents_bounds(GetLocalBounds());
  if (border_.get()) {
    gfx::Insets insets;
    border_->GetInsets(&insets);
    contents_bounds.Inset(insets);
  }
  return contents_bounds;
}

gfx::Rect View::GetLocalBounds() const {
  return gfx::Rect(0, 0, width(), height());
}

gfx::Insets View::GetInsets() const {
  gfx::Insets insets;
  if (border_.get())
    border_->GetInsets(&insets);
  return insets;
}

gfx::Rect View::GetVisibleBounds() const {
  if (!IsVisibleInRootView())
    return gfx::Rect();
  gfx::Rect vis_bounds(0, 0, width(), height());
  gfx::Rect ancestor_bounds;
  const View* view = this;
  ui::Transform transform;

  while (view != NULL && !vis_bounds.IsEmpty()) {
    if (view->transform())
      transform.ConcatTransform(*view->transform());
    transform.ConcatTranslate(static_cast<float>(view->GetMirroredX()),
                              static_cast<float>(view->y()));

    vis_bounds = view->ConvertRectToParent(vis_bounds);
    const View* ancestor = view->parent_;
    if (ancestor != NULL) {
      ancestor_bounds.SetRect(0, 0, ancestor->width(), ancestor->height());
      vis_bounds = vis_bounds.Intersect(ancestor_bounds);
    } else if (!view->GetWidget()) {
      // If the view has no Widget, we're not visible. Return an empty rect.
      return gfx::Rect();
    }
    view = ancestor;
  }
  if (vis_bounds.IsEmpty())
    return vis_bounds;
  // Convert back to this views coordinate system.
  transform.TransformRectReverse(&vis_bounds);
  return vis_bounds;
}

gfx::Rect View::GetScreenBounds() const {
  gfx::Point origin;
  View::ConvertPointToScreen(this, &origin);
  return gfx::Rect(origin, size());
}

gfx::Size View::GetPreferredSize() {
  if (layout_manager_.get())
    return layout_manager_->GetPreferredSize(this);
  return gfx::Size();
}

int View::GetBaseline() const {
  return -1;
}

void View::SizeToPreferredSize() {
  gfx::Size prefsize = GetPreferredSize();
  if ((prefsize.width() != width()) || (prefsize.height() != height()))
    SetBounds(x(), y(), prefsize.width(), prefsize.height());
}

gfx::Size View::GetMinimumSize() {
  return GetPreferredSize();
}

int View::GetHeightForWidth(int w) {
  if (layout_manager_.get())
    return layout_manager_->GetPreferredHeightForWidth(this, w);
  return GetPreferredSize().height();
}

void View::SetVisible(bool visible) {
  if (visible != visible_) {
    // If the tab is currently visible, schedule paint to refresh parent.
    if (visible_)
      SchedulePaint();

    visible_ = visible;

    if (visible_)
      CreateLayerIfNecessary();
    else
      // Destroy layer if tab is invisible as invisible tabs never paint
      DestroyLayerRecurse();

    // This notifies all sub-views recursively.
    PropagateVisibilityNotifications(this, visible_);

    // If we are newly visible, schedule paint.
    if (visible_)
      SchedulePaint();
  }
}

bool View::IsVisible() const {
  return visible_;
}

bool View::IsVisibleInRootView() const {
  return IsVisible() && parent_ ? parent_->IsVisibleInRootView() : false;
}

void View::SetEnabled(bool enabled) {
  if (enabled != enabled_) {
    enabled_ = enabled;
    OnEnabledChanged();
  }
}

bool View::IsEnabled() const {
  return enabled_;
}

void View::OnEnabledChanged() {
  SchedulePaint();
}

// Transformations -------------------------------------------------------------

const ui::Transform& View::GetTransform() const {
  static const ui::Transform* no_op = new ui::Transform;
  return transform() ? *transform() : *no_op;
}

void View::SetTransform(const ui::Transform& transform) {
  if (!transform.HasChange()) {
    if (!layer_helper_.get() || !this->transform())
      return;
    layer_helper_->SetTransform(transform);

    if (!ShouldPaintToLayer())
      DestroyLayerAndReparent();
    else if (layer())
      layer_helper_->property_setter()->SetTransform(layer(), transform);

    SchedulePaint();
  } else {
    // Make sure if the view didn't have its own texture and was painting onto
    // something else, that gets refreshed too.
    if (!ShouldPaintToLayer())
      MarkLayerDirty();

    if (!layer_helper_.get())
      layer_helper_.reset(new internal::LayerHelper());
    layer_helper_->SetTransform(transform);
    if (!layer()) {
      CreateLayer();
      SchedulePaint();
    } else {
      layer_helper_->property_setter()->SetTransform(layer(), transform);
      // We have a layer. When the transform changes and the layer is up to
      // date we don't want to SchedulePaint as it'll trigger painting to the
      // layer. Instead we tell the Widget to paint, which makes the
      // compositor draw using the existing layer.
      // We schedule paint the complete bounds as compositor generally don't
      // support partial painting.
      Widget* widget = GetWidget();
      if (widget)
        widget->SchedulePaintInRect(widget->GetRootView()->bounds());
    }
  }
}

void View::SetPaintToLayer(bool value) {
  bool paint_to_layer = layer_helper_.get() && layer_helper_->paint_to_layer();
  if (value == paint_to_layer)
    return;

  if (value) {
    if (!layer_helper_.get())
      layer_helper_.reset(new internal::LayerHelper());
    layer_helper_->set_paint_to_layer(true);
    CreateLayer();
  } else if (layer_helper_.get()) {
    layer_helper_->set_paint_to_layer(false);
    if (!ShouldPaintToLayer())
      DestroyLayerAndReparent();
  }
}

void View::SetLayerPropertySetter(LayerPropertySetter* setter) {
  if ((layer_helper_.get() && layer_helper_->property_setter() == setter) ||
      (!layer_helper_.get() && setter == NULL)) {
    return;
  }

  if (!layer_helper_.get())
    layer_helper_.reset(new internal::LayerHelper());
  layer_helper_->set_property_setter_explicitly_set(setter != NULL);
  layer_helper_->SetPropertySetter(setter);
}

// RTL positioning -------------------------------------------------------------

gfx::Rect View::GetMirroredBounds() const {
  gfx::Rect bounds(bounds_);
  bounds.set_x(GetMirroredX());
  return bounds;
}

gfx::Point View::GetMirroredPosition() const {
  return gfx::Point(GetMirroredX(), y());
}

int View::GetMirroredX() const {
  return parent_ ? parent_->GetMirroredXForRect(bounds_) : x();
}

int View::GetMirroredXForRect(const gfx::Rect& bounds) const {
  return base::i18n::IsRTL() ?
      (width() - bounds.x() - bounds.width()) : bounds.x();
}

int View::GetMirroredXInView(int x) const {
  return base::i18n::IsRTL() ? width() - x : x;
}

int View::GetMirroredXWithWidthInView(int x, int w) const {
  return base::i18n::IsRTL() ? width() - x - w : x;
}

// Layout ----------------------------------------------------------------------

void View::Layout() {
  needs_layout_ = false;

  // If we have a layout manager, let it handle the layout for us.
  if (layout_manager_.get())
    layout_manager_->Layout(this);

  // Make sure to propagate the Layout() call to any children that haven't
  // received it yet through the layout manager and need to be laid out. This
  // is needed for the case when the child requires a layout but its bounds
  // weren't changed by the layout manager. If there is no layout manager, we
  // just propagate the Layout() call down the hierarchy, so whoever receives
  // the call can take appropriate action.
  for (int i = 0, count = child_count(); i < count; ++i) {
    View* child = child_at(i);
    if (child->needs_layout_ || !layout_manager_.get()) {
      child->needs_layout_ = false;
      child->Layout();
    }
  }
}

void View::InvalidateLayout() {
  // Always invalidate up. This is needed to handle the case of us already being
  // valid, but not our parent.
  needs_layout_ = true;
  if (parent_)
    parent_->InvalidateLayout();
}

LayoutManager* View::GetLayoutManager() const {
  return layout_manager_.get();
}

void View::SetLayoutManager(LayoutManager* layout_manager) {
  if (layout_manager_.get())
    layout_manager_->Uninstalled(this);

  layout_manager_.reset(layout_manager);
  if (layout_manager_.get())
    layout_manager_->Installed(this);
}

// Attributes ------------------------------------------------------------------

std::string View::GetClassName() const {
  return kViewClassName;
}

View* View::GetAncestorWithClassName(const std::string& name) {
  for (View* view = this; view; view = view->parent_) {
    if (view->GetClassName() == name)
      return view;
  }
  return NULL;
}

const View* View::GetViewByID(int id) const {
  if (id == id_)
    return const_cast<View*>(this);

  for (int i = 0, count = child_count(); i < count; ++i) {
    const View* view = child_at(i)->GetViewByID(id);
    if (view)
      return view;
  }
  return NULL;
}

View* View::GetViewByID(int id) {
  return const_cast<View*>(const_cast<const View*>(this)->GetViewByID(id));
}

void View::SetGroup(int gid) {
  // Don't change the group id once it's set.
  DCHECK(group_ == -1 || group_ == gid);
  group_ = gid;
}

int View::GetGroup() const {
  return group_;
}

bool View::IsGroupFocusTraversable() const {
  return true;
}

void View::GetViewsInGroup(int group, Views* views) {
  if (group_ == group)
    views->push_back(this);

  for (int i = 0, count = child_count(); i < count; ++i)
    child_at(i)->GetViewsInGroup(group, views);
}

View* View::GetSelectedViewForGroup(int group) {
  Views views;
  GetWidget()->GetRootView()->GetViewsInGroup(group, &views);
  return views.empty() ? NULL : views[0];
}

// Coordinate conversion -------------------------------------------------------

// static
void View::ConvertPointToView(const View* src,
                              const View* dst,
                              gfx::Point* point) {
  ConvertPointToView(src, dst, point, true);
}

// static
void View::ConvertPointToWidget(const View* src, gfx::Point* p) {
  DCHECK(src);
  DCHECK(p);

  src->ConvertPointForAncestor(NULL, p);
}

// static
void View::ConvertPointFromWidget(const View* dest, gfx::Point* p) {
  DCHECK(dest);
  DCHECK(p);

  dest->ConvertPointFromAncestor(NULL, p);
}

// static
void View::ConvertPointToScreen(const View* src, gfx::Point* p) {
  DCHECK(src);
  DCHECK(p);

  // If the view is not connected to a tree, there's nothing we can do.
  const Widget* widget = src->GetWidget();
  if (widget) {
    ConvertPointToWidget(src, p);
    gfx::Rect r = widget->GetClientAreaScreenBounds();
    p->SetPoint(p->x() + r.x(), p->y() + r.y());
  }
}

gfx::Rect View::ConvertRectToParent(const gfx::Rect& rect) const {
  gfx::Rect x_rect = rect;
  if (transform())
    transform()->TransformRect(&x_rect);
  x_rect.Offset(GetMirroredPosition());
  return x_rect;
}

gfx::Rect View::ConvertRectToWidget(const gfx::Rect& rect) const {
  gfx::Rect x_rect = rect;
  for (const View* v = this; v; v = v->parent_)
    x_rect = v->ConvertRectToParent(x_rect);
  return x_rect;
}

// Painting --------------------------------------------------------------------

void View::SchedulePaint() {
  SchedulePaintInRect(GetLocalBounds());
}

void View::SchedulePaintInRect(const gfx::Rect& rect) {
  if (!IsVisible())
    return;

  MarkLayerDirty();
  SchedulePaintInternal(rect);
}

void View::Paint(gfx::Canvas* canvas) {
  if (!IsVisible())
    return;

  ScopedCanvas scoped_canvas(NULL);
  scoped_ptr<gfx::Canvas> layer_canvas;
  gfx::Rect layer_rect;

  if (layer()) {
    gfx::Rect dirty_rect;
    if (!layer_helper_->clip_rect().IsEmpty()) {
      dirty_rect = layer_helper_->clip_rect();
    } else {
      // TODO: clip against dirty rect of canvas (if canvas is non-null).
      dirty_rect = gfx::Rect(0, 0, width(), height());
    }
    if (dirty_rect.IsEmpty())
      return;

    if (!layer_helper_->bitmap_needs_updating()) {
      // We don't need to be painted. Iterate over descendants in case one of
      // them is dirty.
      PaintToLayer(dirty_rect);
      return;
    }

    layer_canvas.reset(gfx::Canvas::CreateCanvas(dirty_rect.width(),
        dirty_rect.height(), false));
    layer_canvas->AsCanvasSkia()->drawColor(
        SK_ColorBLACK, SkXfermode::kClear_Mode);
    layer_canvas->TranslateInt(-dirty_rect.x(), -dirty_rect.y());
    canvas = layer_canvas.get();
    layer_rect = dirty_rect;
  } else {
    // We're going to modify the canvas, save its state first.
    scoped_canvas.SetCanvas(canvas);

    // Paint this View and its children, setting the clip rect to the bounds
    // of this View and translating the origin to the local bounds' top left
    // point.
    //
    // Note that the X (or left) position we pass to ClipRectInt takes into
    // consideration whether or not the view uses a right-to-left layout so that
    // we paint our view in its mirrored position if need be.
    if (!canvas->ClipRectInt(GetMirroredX(), y(),
                             width() - static_cast<int>(clip_x_),
                             height() - static_cast<int>(clip_y_))) {
      return;
    }
    // Non-empty clip, translate the graphics such that 0,0 corresponds to
    // where this view is located (related to its parent).
    canvas->TranslateInt(GetMirroredX(), y());

    if (transform())
      canvas->Transform(*transform());
  }

  {
    // If the View we are about to paint requested the canvas to be flipped, we
    // should change the transform appropriately.
    // The canvas mirroring is undone once the View is done painting so that we
    // don't pass the canvas with the mirrored transform to Views that didn't
    // request the canvas to be flipped.

    ScopedCanvas scoped(canvas);
    if (FlipCanvasOnPaintForRTLUI()) {
      canvas->TranslateInt(width(), 0);
      canvas->ScaleInt(-1, 1);
    }

    OnPaint(canvas);
  }

  PaintChildren(canvas);

  if (layer_canvas.get()) {
    layer()->SetCanvas(*layer_canvas->AsCanvasSkia(), layer_rect.origin());
    layer_helper_->set_bitmap_needs_updating(false);
  }
}

ThemeProvider* View::GetThemeProvider() const {
  const Widget* widget = GetWidget();
  return widget ? widget->GetThemeProvider() : NULL;
}

// Accelerated Painting --------------------------------------------------------

// static
void View::set_use_acceleration_when_possible(bool use) {
  use_acceleration_when_possible = use;
}

// static
bool View::get_use_acceleration_when_possible() {
  return use_acceleration_when_possible;
}

// Input -----------------------------------------------------------------------

View* View::GetEventHandlerForPoint(const gfx::Point& point) {
  // Walk the child Views recursively looking for the View that most
  // tightly encloses the specified point.
  for (int i = child_count() - 1; i >= 0; --i) {
    View* child = child_at(i);
    if (!child->IsVisible())
      continue;

    gfx::Point point_in_child_coords(point);
    View::ConvertPointToView(this, child, &point_in_child_coords);
    if (child->HitTest(point_in_child_coords))
      return child->GetEventHandlerForPoint(point_in_child_coords);
  }
  return this;
}

gfx::NativeCursor View::GetCursor(const MouseEvent& event) {
#if defined(OS_WIN)
  static HCURSOR arrow = LoadCursor(NULL, IDC_ARROW);
  return arrow;
#else
  return NULL;
#endif
}

bool View::HitTest(const gfx::Point& l) const {
  if (GetLocalBounds().Contains(l)) {
    if (HasHitTestMask()) {
      gfx::Path mask;
      GetHitTestMask(&mask);
      // TODO: can this use SkRegion's contains instead?
#if defined(OS_WIN)
      base::win::ScopedRegion rgn(mask.CreateNativeRegion());
      return !!PtInRegion(rgn, l.x(), l.y());
#elif defined(TOOLKIT_USES_GTK)
      ui::ScopedRegion rgn(mask.CreateNativeRegion());
      return gdk_region_point_in(rgn.Get(), l.x(), l.y());
#endif
    }
    // No mask, but inside our bounds.
    return true;
  }
  // Outside our bounds.
  return false;
}

bool View::OnMousePressed(const MouseEvent& event) {
  return false;
}

bool View::OnMouseDragged(const MouseEvent& event) {
  return false;
}

void View::OnMouseReleased(const MouseEvent& event) {
}

void View::OnMouseCaptureLost() {
}

void View::OnMouseMoved(const MouseEvent& event) {
}

void View::OnMouseEntered(const MouseEvent& event) {
}

void View::OnMouseExited(const MouseEvent& event) {
}

ui::TouchStatus View::OnTouchEvent(const TouchEvent& event) {
  DVLOG(1) << "visited the OnTouchEvent";
  return ui::TOUCH_STATUS_UNKNOWN;
}

void View::SetMouseHandler(View *new_mouse_handler) {
  // It is valid for new_mouse_handler to be NULL
  if (parent_)
    parent_->SetMouseHandler(new_mouse_handler);
}

bool View::OnKeyPressed(const KeyEvent& event) {
  return false;
}

bool View::OnKeyReleased(const KeyEvent& event) {
  return false;
}

bool View::OnMouseWheel(const MouseWheelEvent& event) {
  return false;
}

TextInputClient* View::GetTextInputClient() {
  return NULL;
}

InputMethod* View::GetInputMethod() {
  Widget* widget = GetWidget();
  return widget ? widget->GetInputMethod() : NULL;
}

// Accelerators ----------------------------------------------------------------

void View::AddAccelerator(const Accelerator& accelerator) {
  if (!accelerators_.get())
    accelerators_.reset(new std::vector<Accelerator>());

  DCHECK(std::find(accelerators_->begin(), accelerators_->end(), accelerator) ==
      accelerators_->end())
      << "Registering the same accelerator multiple times";

  accelerators_->push_back(accelerator);
  RegisterPendingAccelerators();
}

void View::RemoveAccelerator(const Accelerator& accelerator) {
  if (!accelerators_.get()) {
    NOTREACHED() << "Removing non-existing accelerator";
    return;
  }

  std::vector<Accelerator>::iterator i(
      std::find(accelerators_->begin(), accelerators_->end(), accelerator));
  if (i == accelerators_->end()) {
    NOTREACHED() << "Removing non-existing accelerator";
    return;
  }

  size_t index = i - accelerators_->begin();
  accelerators_->erase(i);
  if (index >= registered_accelerator_count_) {
    // The accelerator is not registered to FocusManager.
    return;
  }
  --registered_accelerator_count_;

  // Providing we are attached to a Widget and registered with a focus manager,
  // we should de-register from that focus manager now.
  if (GetWidget() && accelerator_focus_manager_)
    accelerator_focus_manager_->UnregisterAccelerator(accelerator, this);
}

void View::ResetAccelerators() {
  if (accelerators_.get())
    UnregisterAccelerators(false);
}

bool View::AcceleratorPressed(const Accelerator& accelerator) {
  return false;
}

// Focus -----------------------------------------------------------------------

bool View::HasFocus() {
  FocusManager* focus_manager = GetFocusManager();
  if (focus_manager)
    return focus_manager->GetFocusedView() == this;
  return false;
}

View* View::GetNextFocusableView() {
  return next_focusable_view_;
}

const View* View::GetNextFocusableView() const {
  return next_focusable_view_;
}

View* View::GetPreviousFocusableView() {
  return previous_focusable_view_;
}

void View::SetNextFocusableView(View* view) {
  view->previous_focusable_view_ = this;
  next_focusable_view_ = view;
}

bool View::IsFocusableInRootView() const {
  return IsFocusable() && IsVisibleInRootView();
}

bool View::IsAccessibilityFocusableInRootView() const {
  return (focusable_ || accessibility_focusable_) && IsEnabled() &&
    IsVisibleInRootView();
}

FocusManager* View::GetFocusManager() {
  Widget* widget = GetWidget();
  return widget ? widget->GetFocusManager() : NULL;
}

void View::RequestFocus() {
  FocusManager* focus_manager = GetFocusManager();
  if (focus_manager && IsFocusableInRootView())
    focus_manager->SetFocusedView(this);
}

bool View::SkipDefaultKeyEventProcessing(const KeyEvent& event) {
  return false;
}

FocusTraversable* View::GetFocusTraversable() {
  return NULL;
}

FocusTraversable* View::GetPaneFocusTraversable() {
  return NULL;
}

// Tooltips --------------------------------------------------------------------

bool View::GetTooltipText(const gfx::Point& p, std::wstring* tooltip) {
  return false;
}

bool View::GetTooltipTextOrigin(const gfx::Point& p, gfx::Point* loc) {
  return false;
}

// Context menus ---------------------------------------------------------------

void View::ShowContextMenu(const gfx::Point& p, bool is_mouse_gesture) {
  if (!context_menu_controller_)
    return;

  context_menu_controller_->ShowContextMenuForView(this, p, is_mouse_gesture);
}

// Drag and drop ---------------------------------------------------------------

bool View::GetDropFormats(
      int* formats,
      std::set<OSExchangeData::CustomFormat>* custom_formats) {
  return false;
}

bool View::AreDropTypesRequired() {
  return false;
}

bool View::CanDrop(const OSExchangeData& data) {
  // TODO(sky): when I finish up migration, this should default to true.
  return false;
}

void View::OnDragEntered(const DropTargetEvent& event) {
}

int View::OnDragUpdated(const DropTargetEvent& event) {
  return ui::DragDropTypes::DRAG_NONE;
}

void View::OnDragExited() {
}

int View::OnPerformDrop(const DropTargetEvent& event) {
  return ui::DragDropTypes::DRAG_NONE;
}

void View::OnDragDone() {
}

// static
bool View::ExceededDragThreshold(int delta_x, int delta_y) {
  return (abs(delta_x) > GetHorizontalDragThreshold() ||
          abs(delta_y) > GetVerticalDragThreshold());
}

// Scrolling -------------------------------------------------------------------

void View::ScrollRectToVisible(const gfx::Rect& rect) {
  // We must take RTL UI mirroring into account when adjusting the position of
  // the region.
  if (parent_) {
    gfx::Rect scroll_rect(rect);
    scroll_rect.Offset(GetMirroredX(), y());
    parent_->ScrollRectToVisible(scroll_rect);
  }
}

int View::GetPageScrollIncrement(ScrollView* scroll_view,
                                 bool is_horizontal, bool is_positive) {
  return 0;
}

int View::GetLineScrollIncrement(ScrollView* scroll_view,
                                 bool is_horizontal, bool is_positive) {
  return 0;
}

////////////////////////////////////////////////////////////////////////////////
// View, protected:

// Size and disposition --------------------------------------------------------

void View::OnBoundsChanged(const gfx::Rect& previous_bounds) {
}

void View::PreferredSizeChanged() {
  InvalidateLayout();
  if (parent_)
    parent_->ChildPreferredSizeChanged(this);
}

bool View::NeedsNotificationWhenVisibleBoundsChange() const {
  return false;
}

void View::OnVisibleBoundsChanged() {
}

// Tree operations -------------------------------------------------------------

void View::ViewHierarchyChanged(bool is_add, View* parent, View* child) {
}

void View::VisibilityChanged(View* starting_from, bool is_visible) {
}

void View::NativeViewHierarchyChanged(bool attached,
                                      gfx::NativeView native_view,
                                      internal::RootView* root_view) {
  FocusManager* focus_manager = GetFocusManager();
  if (!accelerator_registration_delayed_ &&
      accelerator_focus_manager_ &&
      accelerator_focus_manager_ != focus_manager) {
    UnregisterAccelerators(true);
    accelerator_registration_delayed_ = true;
  }
  if (accelerator_registration_delayed_ && attached) {
    if (focus_manager) {
      RegisterPendingAccelerators();
      accelerator_registration_delayed_ = false;
    }
  }
}

// Painting --------------------------------------------------------------------

void View::PaintChildren(gfx::Canvas* canvas) {
  for (int i = 0, count = child_count(); i < count; ++i)
    child_at(i)->Paint(canvas);
}

void View::OnPaint(gfx::Canvas* canvas) {
  OnPaintBackground(canvas);
  OnPaintFocusBorder(canvas);
  OnPaintBorder(canvas);
}

void View::OnPaintBackground(gfx::Canvas* canvas) {
  if (background_.get())
    background_->Paint(canvas, this);
}

void View::OnPaintBorder(gfx::Canvas* canvas) {
  if (border_.get())
    border_->Paint(*this, canvas);
}

void View::OnPaintFocusBorder(gfx::Canvas* canvas) {
  if ((IsFocusable() || IsAccessibilityFocusableInRootView()) && HasFocus())
    canvas->DrawFocusRect(0, 0, width(), height());
}

// Accelerated Painting --------------------------------------------------------

void View::PaintComposite() {
  if (!IsVisible())
    return;

  if (layer()) {
    OnWillCompositeLayer();
    layer()->Draw();
  }

  for (int i = 0, count = child_count(); i < count; ++i)
    child_at(i)->PaintComposite();
}

void View::SchedulePaintInternal(const gfx::Rect& rect) {
  if (parent_ && parent_->IsVisible()) {
    // Translate the requested paint rect to the parent's coordinate system
    // then pass this notification up to the parent.
    parent_->SchedulePaintInternal(ConvertRectToParent(rect));
  }
}

void View::PaintToLayer(const gfx::Rect& dirty_region) {
  if (!IsVisible())
    return;

  if (layer() && layer_helper_->bitmap_needs_updating()) {
    if (!layer_helper_->needs_paint_all())
      layer_helper_->set_clip_rect(dirty_region);
    else
      layer_helper_->set_needs_paint_all(false);
    Paint(NULL);
    layer_helper_->set_clip_rect(gfx::Rect());
  } else {
    // Forward to all children as a descendant may be dirty and have a layer.
    for (int i = child_count() - 1; i >= 0; --i) {
      View* child_view = child_at(i);

      gfx::Rect child_dirty_rect = dirty_region;
      child_dirty_rect.Offset(-child_view->GetMirroredX(), -child_view->y());
      child_view->GetTransform().TransformRectReverse(&child_dirty_rect);
      child_dirty_rect = gfx::Rect(gfx::Point(), child_view->size()).Intersect(
          child_dirty_rect);

      if (!child_dirty_rect.IsEmpty())
        child_at(i)->PaintToLayer(child_dirty_rect);
    }
  }
}

void View::OnWillCompositeLayer() {
}

void View::SetFillsBoundsOpaquely(bool fills_bounds_opaquely) {
  if (!layer_helper_.get())
    layer_helper_.reset(new internal::LayerHelper());

  layer_helper_->set_fills_bounds_opaquely(fills_bounds_opaquely);

  if (layer())
    layer()->SetFillsBoundsOpaquely(fills_bounds_opaquely);
}

bool View::SetExternalTexture(ui::Texture* texture) {
  if (!texture && !layer_helper_.get())
    return true;

  if (!layer_helper_.get())
    layer_helper_.reset(new internal::LayerHelper());
  bool use_external = (texture != NULL);
  if (use_external != layer_helper_->paint_to_layer())
    SetPaintToLayer(use_external);
  else if (use_external && !layer())
    CreateLayer();

  if (use_external && !layer())
    return false;

  // Child views must not paint into the external texture. So make sure each
  // child view has its own layer to paint into.
  if (use_external) {
    for (Views::iterator i = children_.begin(); i != children_.end(); ++i)
      (*i)->SetPaintToLayer(true);
  }

  layer_helper_->set_layer_updated_externally(use_external);
  layer_helper_->set_bitmap_needs_updating(!use_external);
  if (layer())
    layer()->SetTexture(texture);

  if (IsVisible())
    SchedulePaintInternal(GetLocalBounds());

  return true;
}

const ui::Compositor* View::GetCompositor() const {
  return parent_ ? parent_->GetCompositor() : NULL;
}

ui::Compositor* View::GetCompositor() {
  return parent_ ? parent_->GetCompositor() : NULL;
}

void View::MarkLayerDirty() {
  if (!use_acceleration_when_possible)
    return;

  if (ShouldPaintToLayer()) {
    if (!layer_helper_->layer_updated_externally())
      layer_helper_->set_bitmap_needs_updating(true);
    return;
  }
  if (parent_)
    parent_->MarkLayerDirty();
}

void View::CalculateOffsetToAncestorWithLayer(gfx::Point* offset,
                                              View** ancestor) {
  if (layer()) {
    if (ancestor)
      *ancestor = this;
    return;
  }
  if (!parent_)
    return;

  offset->Offset(x(), y());
  parent_->CalculateOffsetToAncestorWithLayer(offset, ancestor);
}

void View::CreateLayerIfNecessary() {
  if (ShouldPaintToLayer())
    CreateLayer();

  for (int i = 0, count = child_count(); i < count; ++i)
    child_at(i)->CreateLayerIfNecessary();
}

void View::MoveLayerToParent(ui::Layer* parent_layer,
                             const gfx::Point& point) {
  gfx::Point local_point(point);
  if (parent_layer != layer())
    local_point.Offset(x(), y());
  if (layer() && parent_layer != layer()) {
    parent_layer->Add(layer());
    layer()->SetBounds(
        gfx::Rect(local_point.x(), local_point.y(), width(), height()));
  } else {
    for (int i = 0, count = child_count(); i < count; ++i)
      child_at(i)->MoveLayerToParent(parent_layer, local_point);
  }
}

void View::DestroyLayerRecurse() {
  for (int i = child_count() - 1; i >= 0; --i)
    child_at(i)->DestroyLayerRecurse();
  DestroyLayer();
}

void View::UpdateLayerBounds(const gfx::Point& offset) {
  if (layer()) {
    layer_helper_->property_setter()->SetBounds(
        layer(),
        gfx::Rect(offset.x() + x(), offset.y() + y(), width(), height()));
  } else {
    gfx::Point new_offset(offset.x() + x(), offset.y() + y());
    for (int i = 0, count = child_count(); i < count; ++i)
      child_at(i)->UpdateLayerBounds(new_offset);
  }
}

// Input -----------------------------------------------------------------------

bool View::HasHitTestMask() const {
  return false;
}

void View::GetHitTestMask(gfx::Path* mask) const {
  DCHECK(mask);
}

// Focus -----------------------------------------------------------------------

bool View::IsFocusable() const {
  return focusable_ && IsEnabled() && IsVisible();
}

void View::OnFocus() {
  // TODO(beng): Investigate whether it's possible for us to move this to
  //             Focus().
  // By default, we clear the native focus. This ensures that no visible native
  // view as the focus and that we still receive keyboard inputs.
  FocusManager* focus_manager = GetFocusManager();
  if (focus_manager)
    focus_manager->ClearNativeFocus();

  // TODO(beng): Investigate whether it's possible for us to move this to
  //             Focus().
  // Notify assistive technologies of the focus change.
  GetWidget()->NotifyAccessibilityEvent(
      this, ui::AccessibilityTypes::EVENT_FOCUS, true);
}

void View::OnBlur() {
}

void View::Focus() {
  SchedulePaint();
  OnFocus();
}

void View::Blur() {
  SchedulePaint();
  OnBlur();
}

// Tooltips --------------------------------------------------------------------

void View::TooltipTextChanged() {
  Widget* widget = GetWidget();
  // TooltipManager may be null if there is a problem creating it.
  if (widget && widget->native_widget_private()->GetTooltipManager()) {
    widget->native_widget_private()->GetTooltipManager()->
        TooltipTextChanged(this);
  }
}

// Context menus ---------------------------------------------------------------

gfx::Point View::GetKeyboardContextMenuLocation() {
  gfx::Rect vis_bounds = GetVisibleBounds();
  gfx::Point screen_point(vis_bounds.x() + vis_bounds.width() / 2,
                          vis_bounds.y() + vis_bounds.height() / 2);
  ConvertPointToScreen(this, &screen_point);
  return screen_point;
}

// Drag and drop ---------------------------------------------------------------

int View::GetDragOperations(const gfx::Point& press_pt) {
  return drag_controller_ ?
      drag_controller_->GetDragOperationsForView(this, press_pt) :
      ui::DragDropTypes::DRAG_NONE;
}

void View::WriteDragData(const gfx::Point& press_pt, OSExchangeData* data) {
  DCHECK(drag_controller_);
  drag_controller_->WriteDragDataForView(this, press_pt, data);
}

bool View::InDrag() {
  Widget* widget = GetWidget();
  return widget ? widget->dragged_view() == this : false;
}

////////////////////////////////////////////////////////////////////////////////
// View, private:

// DropInfo --------------------------------------------------------------------

void View::DragInfo::Reset() {
  possible_drag = false;
  start_pt = gfx::Point();
}

void View::DragInfo::PossibleDrag(const gfx::Point& p) {
  possible_drag = true;
  start_pt = p;
}

// Painting --------------------------------------------------------------------

void View::SchedulePaintBoundsChanged(SchedulePaintType type) {
  if (layer() && type == SCHEDULE_PAINT_SIZE_SAME) {
    // If only the positions changes and we have a layer, we don't need to mark
    // the layer as dirty (which SchedulePaint does), only paint the bounds.
    SchedulePaintInternal(gfx::Rect(0, 0, width(), height()));
  } else {
    // If the size changes, or we don't have a layer then we need to use
    // SchedulePaint to make sure the layer is marked as dirty.
    SchedulePaint();
  }
}

// Tree operations -------------------------------------------------------------

void View::DoRemoveChildView(View* view,
                             bool update_focus_cycle,
                             bool update_tool_tip,
                             bool delete_removed_view) {
  DCHECK(view);
  const Views::iterator i(std::find(children_.begin(), children_.end(), view));
  scoped_ptr<View> view_to_be_deleted;
  if (i != children_.end()) {
    if (update_focus_cycle) {
      // Let's remove the view from the focus traversal.
      View* next_focusable = view->next_focusable_view_;
      View* prev_focusable = view->previous_focusable_view_;
      if (prev_focusable)
        prev_focusable->next_focusable_view_ = next_focusable;
      if (next_focusable)
        next_focusable->previous_focusable_view_ = prev_focusable;
    }

    if (GetWidget())
      UnregisterChildrenForVisibleBoundsNotification(view);
    view->DestroyLayerRecurse();
    view->PropagateRemoveNotifications(this);
    view->parent_ = NULL;

    if (delete_removed_view && view->parent_owned())
      view_to_be_deleted.reset(view);

    children_.erase(i);
  }

  if (update_tool_tip)
    UpdateTooltip();

  if (layout_manager_.get())
    layout_manager_->ViewRemoved(this, view);
}

void View::PropagateRemoveNotifications(View* parent) {
  for (int i = 0, count = child_count(); i < count; ++i)
    child_at(i)->PropagateRemoveNotifications(parent);

  for (View* v = this; v; v = v->parent_)
    v->ViewHierarchyChangedImpl(true, false, parent, this);
}

void View::PropagateAddNotifications(View* parent, View* child) {
  for (int i = 0, count = child_count(); i < count; ++i)
    child_at(i)->PropagateAddNotifications(parent, child);
  ViewHierarchyChangedImpl(true, true, parent, child);
}

void View::PropagateNativeViewHierarchyChanged(bool attached,
                                               gfx::NativeView native_view,
                                               internal::RootView* root_view) {
  for (int i = 0, count = child_count(); i < count; ++i)
    child_at(i)->PropagateNativeViewHierarchyChanged(attached,
                                                           native_view,
                                                           root_view);
  NativeViewHierarchyChanged(attached, native_view, root_view);
}

void View::ViewHierarchyChangedImpl(bool register_accelerators,
                                    bool is_add,
                                    View* parent,
                                    View* child) {
  if (register_accelerators) {
    if (is_add) {
      // If you get this registration, you are part of a subtree that has been
      // added to the view hierarchy.
      if (GetFocusManager()) {
        RegisterPendingAccelerators();
      } else {
        // Delay accelerator registration until visible as we do not have
        // focus manager until then.
        accelerator_registration_delayed_ = true;
      }
    } else {
      if (child == this)
        UnregisterAccelerators(true);
    }
  }

  ViewHierarchyChanged(is_add, parent, child);
  parent->needs_layout_ = true;
}

// Size and disposition --------------------------------------------------------

void View::PropagateVisibilityNotifications(View* start, bool is_visible) {
  for (int i = 0, count = child_count(); i < count; ++i)
    child_at(i)->PropagateVisibilityNotifications(start, is_visible);
  VisibilityChangedImpl(start, is_visible);
}

void View::VisibilityChangedImpl(View* starting_from, bool is_visible) {
  if (is_visible)
    RegisterPendingAccelerators();
  else
    UnregisterAccelerators(true);
  VisibilityChanged(starting_from, is_visible);
}

void View::BoundsChanged(const gfx::Rect& previous_bounds) {
  if (IsVisible()) {
    // Paint the new bounds.
    SchedulePaintBoundsChanged(
        bounds_.size() == previous_bounds.size() ? SCHEDULE_PAINT_SIZE_SAME :
        SCHEDULE_PAINT_SIZE_CHANGED);

    if (use_acceleration_when_possible) {
      if (layer()) {
        if (parent_) {
          gfx::Point offset;
          parent_->CalculateOffsetToAncestorWithLayer(&offset, NULL);
          offset.Offset(x(), y());
          layer_helper_->property_setter()->SetBounds(
              layer(), gfx::Rect(offset, size()));
        } else {
          layer_helper_->property_setter()->SetBounds(layer(), bounds_);
        }
        if (previous_bounds.size() != bounds_.size() &&
            !layer_helper_->layer_updated_externally()) {
          // If our bounds have changed then we need to update the complete
          // texture.
          layer_helper_->set_needs_paint_all(true);
        }
      } else if (GetCompositor()) {
        // If our bounds have changed, then any descendant layer bounds may
        // have changed. Update them accordingly.
        gfx::Point offset;
        CalculateOffsetToAncestorWithLayer(&offset, NULL);
        // CalculateOffsetToAncestorWithLayer includes our location as does
        // UpdateLayerBounds.
        offset.Offset(-x(), -y());
        UpdateLayerBounds(offset);
      }
    }
  }

  OnBoundsChanged(previous_bounds);

  if (previous_bounds.size() != size()) {
    needs_layout_ = false;
    Layout();
  }

  if (NeedsNotificationWhenVisibleBoundsChange()) {
    OnVisibleBoundsChanged();
  }

  // Notify interested Views that visible bounds within the root view may have
  // changed.
  if (descendants_to_notify_.get()) {
    for (Views::iterator i(descendants_to_notify_->begin());
         i != descendants_to_notify_->end(); ++i) {
      (*i)->OnVisibleBoundsChanged();
    }
  }
}

// static
void View::RegisterChildrenForVisibleBoundsNotification(View* view) {
  if (view->NeedsNotificationWhenVisibleBoundsChange())
    view->RegisterForVisibleBoundsNotification();
  for (int i = 0; i < view->child_count(); ++i)
    RegisterChildrenForVisibleBoundsNotification(view->child_at(i));
}

// static
void View::UnregisterChildrenForVisibleBoundsNotification(View* view) {
  if (view->NeedsNotificationWhenVisibleBoundsChange())
    view->UnregisterForVisibleBoundsNotification();
  for (int i = 0; i < view->child_count(); ++i)
    UnregisterChildrenForVisibleBoundsNotification(view->child_at(i));
}

void View::RegisterForVisibleBoundsNotification() {
  if (registered_for_visible_bounds_notification_)
    return;

  registered_for_visible_bounds_notification_ = true;
  for (View* ancestor = parent_; ancestor; ancestor = ancestor->parent_)
    ancestor->AddDescendantToNotify(this);
}

void View::UnregisterForVisibleBoundsNotification() {
  if (!registered_for_visible_bounds_notification_)
    return;

  registered_for_visible_bounds_notification_ = false;
  for (View* ancestor = parent_; ancestor; ancestor = ancestor->parent_)
    ancestor->RemoveDescendantToNotify(this);
}

void View::AddDescendantToNotify(View* view) {
  DCHECK(view);
  if (!descendants_to_notify_.get())
    descendants_to_notify_.reset(new Views);
  descendants_to_notify_->push_back(view);
}

void View::RemoveDescendantToNotify(View* view) {
  DCHECK(view && descendants_to_notify_.get());
  Views::iterator i(std::find(
      descendants_to_notify_->begin(), descendants_to_notify_->end(), view));
  DCHECK(i != descendants_to_notify_->end());
  descendants_to_notify_->erase(i);
  if (descendants_to_notify_->empty())
    descendants_to_notify_.reset();
}

// Transformations -------------------------------------------------------------

bool View::GetTransformRelativeTo(const View* ancestor,
                                  ui::Transform* transform) const {
  const View* p = this;

  while (p && p != ancestor) {
    if (p->transform())
      transform->ConcatTransform(*p->transform());
    transform->ConcatTranslate(static_cast<float>(p->GetMirroredX()),
                               static_cast<float>(p->y()));

    p = p->parent_;
  }

  return p == ancestor;
}

// Coordinate conversion -------------------------------------------------------

// static
void View::ConvertPointToView(const View* src,
                              const View* dst,
                              gfx::Point* point,
                              bool try_other_direction) {
  // src can be NULL
  DCHECK(dst);
  DCHECK(point);

  const Widget* src_widget = src ? src->GetWidget() : NULL ;
  const Widget* dst_widget = dst->GetWidget();
  // If dest and src aren't in the same widget, try to convert the
  // point to the destination widget's coordinates first.
  // TODO(oshima|sadrul): Cleanup and consolidate conversion methods.
  if (Widget::IsPureViews() && src_widget && src_widget != dst_widget) {
    // convert to src_widget first.
    gfx::Point p = *point;
    src->ConvertPointForAncestor(src_widget->GetRootView(), &p);
    if (dst_widget->ConvertPointFromAncestor(src_widget, &p)) {
      // Convertion to destination widget's coordinates was successful.
      // Use destination's root as a source to convert the point further.
      src = dst_widget->GetRootView();
      *point = p;
    }
  }

  if (src == NULL || src->Contains(dst)) {
    dst->ConvertPointFromAncestor(src, point);
    if (!src) {
      if (dst_widget) {
        gfx::Rect b = dst_widget->GetClientAreaScreenBounds();
        point->SetPoint(point->x() - b.x(), point->y() - b.y());
      }
    }
  } else if (src && try_other_direction) {
    if (!src->ConvertPointForAncestor(dst, point)) {
      // |src| is not an ancestor of |dst|, and |dst| is not an ancestor of
      // |src| either. At this stage, |point| is in the widget's coordinate
      // system. So convert from the widget's to |dst|'s coordinate system now.
      ConvertPointFromWidget(dst, point);
    }
  }
}

bool View::ConvertPointForAncestor(const View* ancestor,
                                   gfx::Point* point) const {
  ui::Transform trans;
  // TODO(sad): Have some way of caching the transformation results.
  bool result = GetTransformRelativeTo(ancestor, &trans);
  gfx::Point3f p(*point);
  trans.TransformPoint(p);
  *point = p.AsPoint();
  return result;
}

bool View::ConvertPointFromAncestor(const View* ancestor,
                                    gfx::Point* point) const {
  ui::Transform trans;
  bool result = GetTransformRelativeTo(ancestor, &trans);
  gfx::Point3f p(*point);
  trans.TransformPointReverse(p);
  *point = p.AsPoint();
  return result;
}

// Accelerated painting --------------------------------------------------------

bool View::ShouldPaintToLayer() const {
  return use_acceleration_when_possible &&
      ((layer_helper_.get() && layer_helper_->ShouldPaintToLayer()) ||
       (parent_ && parent_->layer_helper_.get() &&
        parent_->layer_helper_->layer_updated_externally()));
}

void View::CreateLayer() {
  if (!ShouldPaintToLayer() || layer())
    return;

  ui::Compositor* compositor = GetCompositor();
  if (!compositor)
    return;

  DCHECK(layer_helper_.get());

  View* ancestor_with_layer = NULL;
  gfx::Point offset;
  CalculateOffsetToAncestorWithLayer(&offset, &ancestor_with_layer);

  DCHECK(ancestor_with_layer || parent_ == NULL);

  layer_helper_->SetLayer(new ui::Layer(compositor));
  layer()->SetFillsBoundsOpaquely(layer_helper_->fills_bounds_opaquely());
  layer()->SetBounds(gfx::Rect(offset.x(), offset.y(), width(), height()));
  layer()->SetTransform(GetTransform());
  if (ancestor_with_layer)
    ancestor_with_layer->layer()->Add(layer());
  layer_helper_->set_bitmap_needs_updating(true);
  layer_helper_->set_needs_paint_all(true);

  MoveLayerToParent(layer(), gfx::Point());
}

void View::DestroyLayerAndReparent() {
  if (!layer())
    return;

  ui::Layer* new_parent = layer()->parent();
  std::vector<ui::Layer*> children = layer()->children();
  for (size_t i = 0; i < children.size(); ++i)
    new_parent->Add(children[i]);

  DestroyLayer();

  gfx::Point offset;
  CalculateOffsetToAncestorWithLayer(&offset, NULL);
  offset.Offset(-x(), -y());
  UpdateLayerBounds(offset);
}

void View::DestroyLayer() {
  if (!layer_helper_.get())
    return;

  if (!layer_helper_->property_setter_explicitly_set() &&
      !ShouldPaintToLayer() &&
      !layer_helper_->fills_bounds_opaquely())
    layer_helper_.reset();
  else
    layer_helper_->SetLayer(NULL);
}

// Input -----------------------------------------------------------------------

bool View::ProcessMousePressed(const MouseEvent& event, DragInfo* drag_info) {
  const bool enabled = IsEnabled();
  int drag_operations =
      (enabled && event.IsOnlyLeftMouseButton() && HitTest(event.location())) ?
      GetDragOperations(event.location()) : 0;
  ContextMenuController* context_menu_controller = event.IsRightMouseButton() ?
      context_menu_controller_ : 0;

  const bool result = OnMousePressed(event);
  // WARNING: we may have been deleted, don't use any View variables.

  if (!enabled)
    return result;

  if (drag_operations != ui::DragDropTypes::DRAG_NONE) {
    drag_info->PossibleDrag(event.location());
    return true;
  }
  return !!context_menu_controller || result;
}

bool View::ProcessMouseDragged(const MouseEvent& event, DragInfo* drag_info) {
  // Copy the field, that way if we're deleted after drag and drop no harm is
  // done.
  ContextMenuController* context_menu_controller = context_menu_controller_;
  const bool possible_drag = drag_info->possible_drag;
  if (possible_drag && ExceededDragThreshold(
      drag_info->start_pt.x() - event.x(),
      drag_info->start_pt.y() - event.y())) {
    if (!drag_controller_ ||
        drag_controller_->CanStartDragForView(
            this, drag_info->start_pt, event.location()))
      DoDrag(event, drag_info->start_pt);
  } else {
    if (OnMouseDragged(event))
      return true;
    // Fall through to return value based on context menu controller.
  }
  // WARNING: we may have been deleted.
  return (context_menu_controller != NULL) || possible_drag;
}

void View::ProcessMouseReleased(const MouseEvent& event) {
  if (context_menu_controller_ && event.IsOnlyRightMouseButton()) {
    // Assume that if there is a context menu controller we won't be deleted
    // from mouse released.
    gfx::Point location(event.location());
    OnMouseReleased(event);
    if (HitTest(location)) {
      ConvertPointToScreen(this, &location);
      ShowContextMenu(location, true);
    }
  } else {
    OnMouseReleased(event);
  }
  // WARNING: we may have been deleted.
}

ui::TouchStatus View::ProcessTouchEvent(const TouchEvent& event) {
  // TODO(rjkroege): Implement a grab scheme similar to as
  // as is found in MousePressed.
  return OnTouchEvent(event);
}

// Accelerators ----------------------------------------------------------------

void View::RegisterPendingAccelerators() {
  if (!accelerators_.get() ||
      registered_accelerator_count_ == accelerators_->size()) {
    // No accelerators are waiting for registration.
    return;
  }

  if (!GetWidget()) {
    // The view is not yet attached to a widget, defer registration until then.
    return;
  }

  accelerator_focus_manager_ = GetFocusManager();
  if (!accelerator_focus_manager_) {
    // Some crash reports seem to show that we may get cases where we have no
    // focus manager (see bug #1291225).  This should never be the case, just
    // making sure we don't crash.

    // TODO(jcampan): This fails for a view under NativeWidgetGtk with
    //                TYPE_CHILD. (see http://crbug.com/21335) reenable
    //                NOTREACHED assertion and verify accelerators works as
    //                expected.
#if defined(OS_WIN)
    NOTREACHED();
#endif
    return;
  }
  // Only register accelerators if we are visible.
  if (!IsVisibleInRootView())
    return;
  for (std::vector<Accelerator>::const_iterator i(
           accelerators_->begin() + registered_accelerator_count_);
       i != accelerators_->end(); ++i) {
    accelerator_focus_manager_->RegisterAccelerator(*i, this);
  }
  registered_accelerator_count_ = accelerators_->size();
}

void View::UnregisterAccelerators(bool leave_data_intact) {
  if (!accelerators_.get())
    return;

  if (GetWidget()) {
    if (accelerator_focus_manager_) {
      // We may not have a FocusManager if the window containing us is being
      // closed, in which case the FocusManager is being deleted so there is
      // nothing to unregister.
      accelerator_focus_manager_->UnregisterAccelerators(this);
      accelerator_focus_manager_ = NULL;
    }
    if (!leave_data_intact) {
      accelerators_->clear();
      accelerators_.reset();
    }
    registered_accelerator_count_ = 0;
  }
}

// Focus -----------------------------------------------------------------------

void View::InitFocusSiblings(View* v, int index) {
  int count = child_count();

  if (count == 0) {
    v->next_focusable_view_ = NULL;
    v->previous_focusable_view_ = NULL;
  } else {
    if (index == count) {
      // We are inserting at the end, but the end of the child list may not be
      // the last focusable element. Let's try to find an element with no next
      // focusable element to link to.
      View* last_focusable_view = NULL;
      for (Views::iterator i(children_.begin()); i != children_.end(); ++i) {
          if (!(*i)->next_focusable_view_) {
            last_focusable_view = *i;
            break;
          }
      }
      if (last_focusable_view == NULL) {
        // Hum... there is a cycle in the focus list. Let's just insert ourself
        // after the last child.
        View* prev = children_[index - 1];
        v->previous_focusable_view_ = prev;
        v->next_focusable_view_ = prev->next_focusable_view_;
        prev->next_focusable_view_->previous_focusable_view_ = v;
        prev->next_focusable_view_ = v;
      } else {
        last_focusable_view->next_focusable_view_ = v;
        v->next_focusable_view_ = NULL;
        v->previous_focusable_view_ = last_focusable_view;
      }
    } else {
      View* prev = children_[index]->GetPreviousFocusableView();
      v->previous_focusable_view_ = prev;
      v->next_focusable_view_ = children_[index];
      if (prev)
        prev->next_focusable_view_ = v;
      children_[index]->previous_focusable_view_ = v;
    }
  }
}

// System events ---------------------------------------------------------------

void View::PropagateThemeChanged() {
  for (int i = child_count() - 1; i >= 0; --i)
    child_at(i)->PropagateThemeChanged();
  OnThemeChanged();
}

void View::PropagateLocaleChanged() {
  for (int i = child_count() - 1; i >= 0; --i)
    child_at(i)->PropagateLocaleChanged();
  OnLocaleChanged();
}

// Tooltips --------------------------------------------------------------------

void View::UpdateTooltip() {
  Widget* widget = GetWidget();
  // TODO(beng): The TooltipManager NULL check can be removed when we
  //             consolidate Init() methods and make views_unittests Init() all
  //             Widgets that it uses.
  if (widget && widget->native_widget_private()->GetTooltipManager())
    widget->native_widget_private()->GetTooltipManager()->UpdateTooltip();
}

// Drag and drop ---------------------------------------------------------------

void View::DoDrag(const MouseEvent& event, const gfx::Point& press_pt) {
  int drag_operations = GetDragOperations(press_pt);
  if (drag_operations == ui::DragDropTypes::DRAG_NONE)
    return;

  OSExchangeData data;
  WriteDragData(press_pt, &data);

  // Message the RootView to do the drag and drop. That way if we're removed
  // the RootView can detect it and avoid calling us back.
  GetWidget()->RunShellDrag(this, data, drag_operations);
}

// Debugging -------------------------------------------------------------------

#if defined(TOUCH_DEBUG)
std::string View::PrintViewGraph(bool first) {
  // 64-bit pointer = 16 bytes of hex + "0x" + '\0' = 19.
  const size_t kMaxPointerStringLength = 19;

  std::string result;

  if (first)
    result.append("digraph {\n");

  // Node characteristics.
  char p[kMaxPointerStringLength];

  size_t baseNameIndex = GetClassName().find_last_of('/');
  if (baseNameIndex == std::string::npos)
    baseNameIndex = 0;
  else
    baseNameIndex++;

  // Information about current node.
  snprintf(p, kMaxPointerStringLength, "%p", this);
  result.append("  N");
  result.append(p+2);
  result.append(" [label=\"");
  result.append(GetClassName().substr(baseNameIndex).c_str());
  result.append("\"");
  if (!parent_)
    result.append(", shape=box");
  if (layer())
    result.append(", color=green");
  result.append("]\n");

  // Link to parent.
  if (parent_) {
    char pp[kMaxPointerStringLength];

    snprintf(pp, kMaxPointerStringLength, "%p", parent_);
    result.append("  N");
    result.append(pp+2);
    result.append(" -> N");
    result.append(p+2);
    result.append("\n");
  }

  // Children.
  for (int i = 0, count = child_count(); i < count; ++i)
    result.append(child_at(i)->PrintViewGraph(false));

  if (first)
    result.append("}\n");

  return result;
}
#endif

}  // namespace views