third_party/blink/renderer/core/inspector/inspector_layer_tree_agent.cc - chromium/src - Git at Google

 /*
  * Copyright (C) 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "third_party/blink/renderer/core/inspector/inspector_layer_tree_agent.h"

 #include <memory>

 #include "base/stl_util.h"
 #include "cc/base/region.h"
 #include "cc/layers/picture_layer.h"
 #include "third_party/blink/public/platform/web_float_point.h"
 #include "third_party/blink/renderer/core/dom/document.h"
 #include "third_party/blink/renderer/core/dom/dom_node_ids.h"
 #include "third_party/blink/renderer/core/frame/local_frame.h"
 #include "third_party/blink/renderer/core/frame/local_frame_view.h"
 #include "third_party/blink/renderer/core/frame/visual_viewport.h"
 #include "third_party/blink/renderer/core/inspector/identifiers_factory.h"
 #include "third_party/blink/renderer/core/inspector/inspected_frames.h"
 #include "third_party/blink/renderer/core/layout/layout_embedded_content.h"
 #include "third_party/blink/renderer/core/layout/layout_view.h"
 #include "third_party/blink/renderer/core/loader/document_loader.h"
 #include "third_party/blink/renderer/core/page/chrome_client.h"
 #include "third_party/blink/renderer/core/page/page.h"
 #include "third_party/blink/renderer/core/paint/paint_layer_scrollable_area.h"
 #include "third_party/blink/renderer/platform/geometry/int_rect.h"
 #include "third_party/blink/renderer/platform/graphics/compositing_reasons.h"
 #include "third_party/blink/renderer/platform/graphics/compositor_element_id.h"
 #include "third_party/blink/renderer/platform/graphics/graphics_layer.h"
 #include "third_party/blink/renderer/platform/graphics/picture_snapshot.h"
 #include "third_party/blink/renderer/platform/transforms/transformation_matrix.h"
 #include "third_party/blink/renderer/platform/wtf/text/string_builder.h"
 #include "third_party/skia/include/core/SkPicture.h"
 #include "third_party/skia/include/core/SkRefCnt.h"
 #include "ui/gfx/geometry/rect.h"

 namespace blink {

 using protocol::Array;
 using protocol::Maybe;
 using protocol::Response;
 unsigned InspectorLayerTreeAgent::last_snapshot_id_;

 inline String IdForLayer(const cc::Layer* layer) {
   return String::Number(layer->id());
 }

 static std::unique_ptr<protocol::DOM::Rect> BuildObjectForRect(
     const gfx::Rect& rect) {
   return protocol::DOM::Rect::create()
       .setX(rect.x())
       .setY(rect.y())
       .setHeight(rect.height())
       .setWidth(rect.width())
       .build();
 }

 static std::unique_ptr<protocol::LayerTree::ScrollRect> BuildScrollRect(
     const gfx::Rect& rect,
     const String& type) {
   std::unique_ptr<protocol::DOM::Rect> rect_object = BuildObjectForRect(rect);
   std::unique_ptr<protocol::LayerTree::ScrollRect> scroll_rect_object =
       protocol::LayerTree::ScrollRect::create()
           .setRect(std::move(rect_object))
           .setType(type)
           .build();
   return scroll_rect_object;
 }

 static std::unique_ptr<Array<protocol::LayerTree::ScrollRect>>
 BuildScrollRectsForLayer(const cc::Layer* layer, bool report_wheel_scrollers) {
   std::unique_ptr<Array<protocol::LayerTree::ScrollRect>> scroll_rects =
       Array<protocol::LayerTree::ScrollRect>::create();
   const cc::Region& non_fast_scrollable_rects =
       layer->non_fast_scrollable_region();
   for (const gfx::Rect& rect : non_fast_scrollable_rects) {
     scroll_rects->addItem(BuildScrollRect(
         IntRect(rect),
         protocol::LayerTree::ScrollRect::TypeEnum::RepaintsOnScroll));
   }
   const cc::Region& touch_event_handler_region =
       layer->touch_action_region().region();

   for (const gfx::Rect& rect : touch_event_handler_region) {
     scroll_rects->addItem(BuildScrollRect(
         IntRect(rect),
         protocol::LayerTree::ScrollRect::TypeEnum::TouchEventHandler));
   }
   if (report_wheel_scrollers) {
     scroll_rects->addItem(BuildScrollRect(
         // TODO(yutak): This truncates the floating point position to integers.
         gfx::Rect(layer->position().x(), layer->position().y(),
                   layer->bounds().width(), layer->bounds().height()),
         protocol::LayerTree::ScrollRect::TypeEnum::WheelEventHandler));
   }
   return scroll_rects->length() ? std::move(scroll_rects) : nullptr;
 }

 // TODO(flackr): We should be getting the sticky position constraints from the
 // property tree once blink is able to access them. https://crbug.com/754339
 static const cc::Layer* FindLayerByElementId(const cc::Layer* root,
                                              CompositorElementId element_id) {
   if (root->element_id() == element_id)
     return root;
   for (auto child : root->children()) {
     if (const auto* layer = FindLayerByElementId(child.get(), element_id))
       return layer;
   }
   return nullptr;
 }

 static std::unique_ptr<protocol::LayerTree::StickyPositionConstraint>
 BuildStickyInfoForLayer(const cc::Layer* root, const cc::Layer* layer) {
   cc::LayerStickyPositionConstraint constraints =
       layer->sticky_position_constraint();
   if (!constraints.is_sticky)
     return nullptr;

   std::unique_ptr<protocol::DOM::Rect> sticky_box_rect =
       BuildObjectForRect(constraints.scroll_container_relative_sticky_box_rect);

   std::unique_ptr<protocol::DOM::Rect> containing_block_rect =
       BuildObjectForRect(
           constraints.scroll_container_relative_containing_block_rect);

   std::unique_ptr<protocol::LayerTree::StickyPositionConstraint>
       constraints_obj =
           protocol::LayerTree::StickyPositionConstraint::create()
               .setStickyBoxRect(std::move(sticky_box_rect))
               .setContainingBlockRect(std::move(containing_block_rect))
               .build();
   if (constraints.nearest_element_shifting_sticky_box) {
     constraints_obj->setNearestLayerShiftingStickyBox(String::Number(
         FindLayerByElementId(root,
                              constraints.nearest_element_shifting_sticky_box)
             ->id()));
   }
   if (constraints.nearest_element_shifting_containing_block) {
     constraints_obj->setNearestLayerShiftingContainingBlock(String::Number(
         FindLayerByElementId(
             root, constraints.nearest_element_shifting_containing_block)
             ->id()));
   }

   return constraints_obj;
 }

 static std::unique_ptr<protocol::LayerTree::Layer> BuildObjectForLayer(
     const cc::Layer* root,
     const cc::Layer* layer,
     bool report_wheel_event_listeners) {
   bool using_layer_list =
       RuntimeEnabledFeatures::CompositeAfterPaintEnabled() ||
       RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled();

   // When the front-end doesn't show internal layers, it will use the the first
   // DrawsContent layer as the root of the shown layer tree. This doesn't work
   // for layer list because the non-DrawsContent root layer is the parent of
   // all DrawsContent layers. We have to cheat the front-end by setting
   // drawsContent to true for the root layer.
   bool draws_content =
       (using_layer_list && root == layer) || layer->DrawsContent();

   std::unique_ptr<protocol::LayerTree::Layer> layer_object =
       protocol::LayerTree::Layer::create()
           .setLayerId(IdForLayer(layer))
           .setOffsetX(using_layer_list ? 0 : layer->position().x())
           .setOffsetY(using_layer_list ? 0 : layer->position().y())
           .setWidth(layer->bounds().width())
           .setHeight(layer->bounds().height())
           .setPaintCount(layer->paint_count())
           .setDrawsContent(draws_content)
           .build();

   if (auto node_id = layer->owner_node_id())
     layer_object->setBackendNodeId(node_id);

   if (const auto* parent = layer->parent())
     layer_object->setParentLayerId(IdForLayer(parent));

   gfx::Transform transform;
   gfx::Point3F transform_origin;
   if (using_layer_list) {
     transform = layer->ScreenSpaceTransform();
   } else {
     transform = layer->transform();
     transform_origin = layer->transform_origin();
   }

   if (!transform.IsIdentity()) {
     auto transform_array = Array<double>::create();
     for (int col = 0; col < 4; ++col) {
       for (int row = 0; row < 4; ++row)
         transform_array->addItem(transform.matrix().get(row, col));
     }
     layer_object->setTransform(std::move(transform_array));
     // FIXME: rename these to setTransformOrigin*
     if (layer->bounds().width() > 0) {
       layer_object->setAnchorX(transform_origin.x() / layer->bounds().width());
     } else {
       layer_object->setAnchorX(0.f);
     }
     if (layer->bounds().height() > 0) {
       layer_object->setAnchorY(transform_origin.y() / layer->bounds().height());
     } else {
       layer_object->setAnchorY(0.f);
     }
     layer_object->setAnchorZ(transform_origin.z());
   }
   std::unique_ptr<Array<protocol::LayerTree::ScrollRect>> scroll_rects =
       BuildScrollRectsForLayer(layer, report_wheel_event_listeners);
   if (scroll_rects)
     layer_object->setScrollRects(std::move(scroll_rects));
   std::unique_ptr<protocol::LayerTree::StickyPositionConstraint> sticky_info =
       BuildStickyInfoForLayer(root, layer);
   if (sticky_info)
     layer_object->setStickyPositionConstraint(std::move(sticky_info));
   return layer_object;
 }

 InspectorLayerTreeAgent::InspectorLayerTreeAgent(
     InspectedFrames* inspected_frames,
     Client* client)
     : inspected_frames_(inspected_frames),
       client_(client),
       suppress_layer_paint_events_(false) {}

 InspectorLayerTreeAgent::~InspectorLayerTreeAgent() = default;

 void InspectorLayerTreeAgent::Trace(blink::Visitor* visitor) {
   visitor->Trace(inspected_frames_);
   InspectorBaseAgent::Trace(visitor);
 }

 void InspectorLayerTreeAgent::Restore() {
   // We do not re-enable layer agent automatically after navigation. This is
   // because it depends on DOMAgent and node ids in particular, so we let
   // front-end request document and re-enable the agent manually after this.
 }

 Response InspectorLayerTreeAgent::enable() {
   instrumenting_agents_->addInspectorLayerTreeAgent(this);
   Document* document = inspected_frames_->Root()->GetDocument();
   if (!document)
     return Response::Error("The root frame doesn't have document");

   if (RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled() ||
       RuntimeEnabledFeatures::CompositeAfterPaintEnabled()) {
     if (document->Lifecycle().GetState() >= DocumentLifecycle::kPaintClean)
       LayerTreePainted();
   } else if (document->Lifecycle().GetState() >=
              DocumentLifecycle::kCompositingClean) {
     LayerTreeDidChange();
   }
   return Response::OK();
 }

 Response InspectorLayerTreeAgent::disable() {
   instrumenting_agents_->removeInspectorLayerTreeAgent(this);
   snapshot_by_id_.clear();
   return Response::OK();
 }

 void InspectorLayerTreeAgent::LayerTreeDidChange() {
   DCHECK(!RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled() &&
          !RuntimeEnabledFeatures::CompositeAfterPaintEnabled());
   GetFrontend()->layerTreeDidChange(BuildLayerTree());
 }

 void InspectorLayerTreeAgent::DidPaint(const cc::Layer* layer,
                                        const LayoutRect& rect) {
   DCHECK(!RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled() &&
          !RuntimeEnabledFeatures::CompositeAfterPaintEnabled());
   if (suppress_layer_paint_events_)
     return;

   // Should only happen for LocalFrameView paints when compositing is off.
   // Consider different instrumentation method for that.
   if (!layer)
     return;

   std::unique_ptr<protocol::DOM::Rect> dom_rect = protocol::DOM::Rect::create()
                                                       .setX(rect.X())
                                                       .setY(rect.Y())
                                                       .setWidth(rect.Width())
                                                       .setHeight(rect.Height())
                                                       .build();
   GetFrontend()->layerPainted(IdForLayer(layer), std::move(dom_rect));
 }

 void InspectorLayerTreeAgent::LayerTreePainted() {
   DCHECK(RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled() ||
          RuntimeEnabledFeatures::CompositeAfterPaintEnabled());

   GetFrontend()->layerTreeDidChange(BuildLayerTree());

   for (const auto& layer :
        inspected_frames_->Root()->View()->RootCcLayer()->children()) {
     if (!layer->update_rect().IsEmpty()) {
       GetFrontend()->layerPainted(IdForLayer(layer.get()),
                                   BuildObjectForRect(layer->update_rect()));
     }
   }
 }

 std::unique_ptr<Array<protocol::LayerTree::Layer>>
 InspectorLayerTreeAgent::BuildLayerTree() {
   const auto* root_layer = RootLayer();
   if (!root_layer)
     return nullptr;

   std::unique_ptr<Array<protocol::LayerTree::Layer>> layers =
       Array<protocol::LayerTree::Layer>::create();
   auto* root_frame = inspected_frames_->Root();
   auto* layer_for_scrolling =
       root_frame->View()->LayoutViewport()->LayerForScrolling();
   int scrolling_layer_id =
       layer_for_scrolling ? layer_for_scrolling->CcLayer()->id() : 0;
   bool have_blocking_wheel_event_handlers =
       root_frame->GetChromeClient().EventListenerProperties(
           root_frame, cc::EventListenerClass::kMouseWheel) ==
       cc::EventListenerProperties::kBlocking;

   GatherLayers(root_layer, layers, have_blocking_wheel_event_handlers,
                scrolling_layer_id);
   return layers;
 }

 void InspectorLayerTreeAgent::GatherLayers(
     const cc::Layer* layer,
     std::unique_ptr<Array<protocol::LayerTree::Layer>>& layers,
     bool has_wheel_event_handlers,
     int scrolling_layer_id) {
   if (client_->IsInspectorLayer(layer))
     return;
   int layer_id = layer->id();
   layers->addItem(BuildObjectForLayer(
       RootLayer(), layer,
       has_wheel_event_handlers && layer_id == scrolling_layer_id));
   for (auto child : layer->children()) {
     GatherLayers(child.get(), layers, has_wheel_event_handlers,
                  scrolling_layer_id);
   }
 }

 const cc::Layer* InspectorLayerTreeAgent::RootLayer() {
   return inspected_frames_->Root()->View()->RootCcLayer();
 }

 static const cc::Layer* FindLayerById(const cc::Layer* root, int layer_id) {
   if (root->id() == layer_id)
     return root;
   for (auto child : root->children()) {
     if (const auto* layer = FindLayerById(child.get(), layer_id))
       return layer;
   }
   return nullptr;
 }

 Response InspectorLayerTreeAgent::LayerById(const String& layer_id,
                                             const cc::Layer*& result) {
   bool ok;
   int id = layer_id.ToInt(&ok);
   if (!ok)
     return Response::Error("Invalid layer id");

   result = FindLayerById(RootLayer(), id);
   if (!result)
     return Response::Error("No layer matching given id found");
   return Response::OK();
 }

 Response InspectorLayerTreeAgent::compositingReasons(
     const String& layer_id,
     std::unique_ptr<Array<String>>* reason_strings) {
   const cc::Layer* layer = nullptr;
   Response response = LayerById(layer_id, layer);
   if (!response.isSuccess())
     return response;
   CompositingReasons reasons = layer->compositing_reasons();
   *reason_strings = Array<String>::create();
   for (const char* name : CompositingReason::ShortNames(reasons))
     (*reason_strings)->addItem(name);
   return Response::OK();
 }

 Response InspectorLayerTreeAgent::makeSnapshot(const String& layer_id,
                                                String* snapshot_id) {
   const cc::Layer* layer = nullptr;
   Response response = LayerById(layer_id, layer);
   if (!response.isSuccess())
     return response;
   if (!layer->DrawsContent())
     return Response::Error("Layer does not draw content");

   suppress_layer_paint_events_ = true;

   // If we hit a devtool break point in the middle of document lifecycle, for
   // example, https://crbug.com/788219, this will prevent crash when clicking
   // the "layer" panel.
   if (inspected_frames_->Root()->GetDocument() && inspected_frames_->Root()
                                                       ->GetDocument()
                                                       ->Lifecycle()
                                                       .LifecyclePostponed())
     return Response::Error("Layer does not draw content");

   inspected_frames_->Root()->View()->UpdateAllLifecyclePhases(
       DocumentLifecycle::LifecycleUpdateReason::kOther);

   suppress_layer_paint_events_ = false;

   auto picture = layer->GetPicture();
   if (!picture)
     return Response::Error("Layer does not produce picture");

   auto snapshot = base::MakeRefCounted<PictureSnapshot>(std::move(picture));
   *snapshot_id = String::Number(++last_snapshot_id_);
   bool new_entry = snapshot_by_id_.insert(*snapshot_id, snapshot).is_new_entry;
   DCHECK(new_entry);
   return Response::OK();
 }

 Response InspectorLayerTreeAgent::loadSnapshot(
     std::unique_ptr<Array<protocol::LayerTree::PictureTile>> tiles,
     String* snapshot_id) {
   if (!tiles->length())
     return Response::Error("Invalid argument, no tiles provided");
   if (tiles->length() > UINT_MAX)
     return Response::Error("Invalid argument, too many tiles provided");
   wtf_size_t tiles_length = static_cast<wtf_size_t>(tiles->length());
   Vector<scoped_refptr<PictureSnapshot::TilePictureStream>> decoded_tiles;
   decoded_tiles.Grow(tiles_length);
   for (wtf_size_t i = 0; i < tiles_length; ++i) {
     protocol::LayerTree::PictureTile* tile = tiles->get(i);
     decoded_tiles[i] = base::AdoptRef(new PictureSnapshot::TilePictureStream());
     decoded_tiles[i]->layer_offset.Set(tile->getX(), tile->getY());
     const protocol::Binary& data = tile->getPicture();
     decoded_tiles[i]->picture =
         SkPicture::MakeFromData(data.data(), data.size());
   }
   scoped_refptr<PictureSnapshot> snapshot =
       PictureSnapshot::Load(decoded_tiles);
   if (!snapshot)
     return Response::Error("Invalid snapshot format");
   if (snapshot->IsEmpty())
     return Response::Error("Empty snapshot");

   *snapshot_id = String::Number(++last_snapshot_id_);
   bool new_entry = snapshot_by_id_.insert(*snapshot_id, snapshot).is_new_entry;
   DCHECK(new_entry);
   return Response::OK();
 }

 Response InspectorLayerTreeAgent::releaseSnapshot(const String& snapshot_id) {
   SnapshotById::iterator it = snapshot_by_id_.find(snapshot_id);
   if (it == snapshot_by_id_.end())
     return Response::Error("Snapshot not found");
   snapshot_by_id_.erase(it);
   return Response::OK();
 }

 Response InspectorLayerTreeAgent::GetSnapshotById(
     const String& snapshot_id,
     const PictureSnapshot*& result) {
   SnapshotById::iterator it = snapshot_by_id_.find(snapshot_id);
   if (it == snapshot_by_id_.end())
     return Response::Error("Snapshot not found");
   result = it->value.get();
   return Response::OK();
 }

 Response InspectorLayerTreeAgent::replaySnapshot(const String& snapshot_id,
                                                  Maybe<int> from_step,
                                                  Maybe<int> to_step,
                                                  Maybe<double> scale,
                                                  String* data_url) {
   const PictureSnapshot* snapshot = nullptr;
   Response response = GetSnapshotById(snapshot_id, snapshot);
   if (!response.isSuccess())
     return response;
   Vector<char> base64_data = snapshot->Replay(
       from_step.fromMaybe(0), to_step.fromMaybe(0), scale.fromMaybe(1.0));
   if (base64_data.IsEmpty())
     return Response::Error("Image encoding failed");
   static constexpr char kUrlPrefix[] = "data:image/png;base64,";
   StringBuilder url;
   url.ReserveCapacity(sizeof(kUrlPrefix) + base64_data.size());
   url.Append(kUrlPrefix);
   url.Append(base64_data.begin(), base64_data.size());
   *data_url = url.ToString();
   return Response::OK();
 }

 static void ParseRect(protocol::DOM::Rect* object, FloatRect* rect) {
   *rect = FloatRect(object->getX(), object->getY(), object->getWidth(),
                     object->getHeight());
 }

 Response InspectorLayerTreeAgent::profileSnapshot(
     const String& snapshot_id,
     Maybe<int> min_repeat_count,
     Maybe<double> min_duration,
     Maybe<protocol::DOM::Rect> clip_rect,
     std::unique_ptr<protocol::Array<protocol::Array<double>>>* out_timings) {
   const PictureSnapshot* snapshot = nullptr;
   Response response = GetSnapshotById(snapshot_id, snapshot);
   if (!response.isSuccess())
     return response;
   FloatRect rect;
   if (clip_rect.isJust())
     ParseRect(clip_rect.fromJust(), &rect);
   auto timings =
       snapshot->Profile(min_repeat_count.fromMaybe(1),
                         TimeDelta::FromSecondsD(min_duration.fromMaybe(0)),
                         clip_rect.isJust() ? &rect : nullptr);
   *out_timings = Array<Array<double>>::create();
   for (const auto& row : timings) {
     std::unique_ptr<Array<double>> out_row = Array<double>::create();
     for (TimeDelta delta : row)
       out_row->addItem(delta.InSecondsF());
     (*out_timings)->addItem(std::move(out_row));
   }
   return Response::OK();
 }

 Response InspectorLayerTreeAgent::snapshotCommandLog(
     const String& snapshot_id,
     std::unique_ptr<Array<protocol::DictionaryValue>>* command_log) {
   const PictureSnapshot* snapshot = nullptr;
   Response response = GetSnapshotById(snapshot_id, snapshot);
   if (!response.isSuccess())
     return response;
   protocol::ErrorSupport errors;
   std::unique_ptr<protocol::Value> log_value = protocol::StringUtil::parseJSON(
       snapshot->SnapshotCommandLog()->ToJSONString());
   *command_log =
       Array<protocol::DictionaryValue>::fromValue(log_value.get(), &errors);
   if (errors.hasErrors())
     return Response::Error(errors.errors());
   return Response::OK();
 }

 }  // namespace blink
	/*
	* Copyright (C) 2012 Apple Inc. All rights reserved.
	* Copyright (C) 2013 Google Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met:
	*
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following disclaimer
	* in the documentation and/or other materials provided with the
	* distribution.
	* * Neither the name of Google Inc. nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "third_party/blink/renderer/core/inspector/inspector_layer_tree_agent.h"

	#include <memory>

	#include "base/stl_util.h"
	#include "cc/base/region.h"
	#include "cc/layers/picture_layer.h"
	#include "third_party/blink/public/platform/web_float_point.h"
	#include "third_party/blink/renderer/core/dom/document.h"
	#include "third_party/blink/renderer/core/dom/dom_node_ids.h"
	#include "third_party/blink/renderer/core/frame/local_frame.h"
	#include "third_party/blink/renderer/core/frame/local_frame_view.h"
	#include "third_party/blink/renderer/core/frame/visual_viewport.h"
	#include "third_party/blink/renderer/core/inspector/identifiers_factory.h"
	#include "third_party/blink/renderer/core/inspector/inspected_frames.h"
	#include "third_party/blink/renderer/core/layout/layout_embedded_content.h"
	#include "third_party/blink/renderer/core/layout/layout_view.h"
	#include "third_party/blink/renderer/core/loader/document_loader.h"
	#include "third_party/blink/renderer/core/page/chrome_client.h"
	#include "third_party/blink/renderer/core/page/page.h"
	#include "third_party/blink/renderer/core/paint/paint_layer_scrollable_area.h"
	#include "third_party/blink/renderer/platform/geometry/int_rect.h"
	#include "third_party/blink/renderer/platform/graphics/compositing_reasons.h"
	#include "third_party/blink/renderer/platform/graphics/compositor_element_id.h"
	#include "third_party/blink/renderer/platform/graphics/graphics_layer.h"
	#include "third_party/blink/renderer/platform/graphics/picture_snapshot.h"
	#include "third_party/blink/renderer/platform/transforms/transformation_matrix.h"
	#include "third_party/blink/renderer/platform/wtf/text/string_builder.h"
	#include "third_party/skia/include/core/SkPicture.h"
	#include "third_party/skia/include/core/SkRefCnt.h"
	#include "ui/gfx/geometry/rect.h"

	namespace blink {

	using protocol::Array;
	using protocol::Maybe;
	using protocol::Response;
	unsigned InspectorLayerTreeAgent::last_snapshot_id_;

	inline String IdForLayer(const cc::Layer* layer) {
	return String::Number(layer->id());
	}

	static std::unique_ptr<protocol::DOM::Rect> BuildObjectForRect(
	const gfx::Rect& rect) {
	return protocol::DOM::Rect::create()
	.setX(rect.x())
	.setY(rect.y())
	.setHeight(rect.height())
	.setWidth(rect.width())
	.build();
	}

	static std::unique_ptr<protocol::LayerTree::ScrollRect> BuildScrollRect(
	const gfx::Rect& rect,
	const String& type) {
	std::unique_ptr<protocol::DOM::Rect> rect_object = BuildObjectForRect(rect);
	std::unique_ptr<protocol::LayerTree::ScrollRect> scroll_rect_object =
	protocol::LayerTree::ScrollRect::create()
	.setRect(std::move(rect_object))
	.setType(type)
	.build();
	return scroll_rect_object;
	}

	static std::unique_ptr<Array<protocol::LayerTree::ScrollRect>>
	BuildScrollRectsForLayer(const cc::Layer* layer, bool report_wheel_scrollers) {
	std::unique_ptr<Array<protocol::LayerTree::ScrollRect>> scroll_rects =
	Array<protocol::LayerTree::ScrollRect>::create();
	const cc::Region& non_fast_scrollable_rects =
	layer->non_fast_scrollable_region();
	for (const gfx::Rect& rect : non_fast_scrollable_rects) {
	scroll_rects->addItem(BuildScrollRect(
	IntRect(rect),
	protocol::LayerTree::ScrollRect::TypeEnum::RepaintsOnScroll));
	}
	const cc::Region& touch_event_handler_region =
	layer->touch_action_region().region();

	for (const gfx::Rect& rect : touch_event_handler_region) {
	scroll_rects->addItem(BuildScrollRect(
	IntRect(rect),
	protocol::LayerTree::ScrollRect::TypeEnum::TouchEventHandler));
	}
	if (report_wheel_scrollers) {
	scroll_rects->addItem(BuildScrollRect(
	// TODO(yutak): This truncates the floating point position to integers.
	gfx::Rect(layer->position().x(), layer->position().y(),
	layer->bounds().width(), layer->bounds().height()),
	protocol::LayerTree::ScrollRect::TypeEnum::WheelEventHandler));
	}
	return scroll_rects->length() ? std::move(scroll_rects) : nullptr;
	}

	// TODO(flackr): We should be getting the sticky position constraints from the
	// property tree once blink is able to access them. https://crbug.com/754339
	static const cc::Layer* FindLayerByElementId(const cc::Layer* root,
	CompositorElementId element_id) {
	if (root->element_id() == element_id)
	return root;
	for (auto child : root->children()) {
	if (const auto* layer = FindLayerByElementId(child.get(), element_id))
	return layer;
	}
	return nullptr;
	}

	static std::unique_ptr<protocol::LayerTree::StickyPositionConstraint>
	BuildStickyInfoForLayer(const cc::Layer* root, const cc::Layer* layer) {
	cc::LayerStickyPositionConstraint constraints =
	layer->sticky_position_constraint();
	if (!constraints.is_sticky)
	return nullptr;

	std::unique_ptr<protocol::DOM::Rect> sticky_box_rect =
	BuildObjectForRect(constraints.scroll_container_relative_sticky_box_rect);

	std::unique_ptr<protocol::DOM::Rect> containing_block_rect =
	BuildObjectForRect(
	constraints.scroll_container_relative_containing_block_rect);

	std::unique_ptr<protocol::LayerTree::StickyPositionConstraint>
	constraints_obj =
	protocol::LayerTree::StickyPositionConstraint::create()
	.setStickyBoxRect(std::move(sticky_box_rect))
	.setContainingBlockRect(std::move(containing_block_rect))
	.build();
	if (constraints.nearest_element_shifting_sticky_box) {
	constraints_obj->setNearestLayerShiftingStickyBox(String::Number(
	FindLayerByElementId(root,
	constraints.nearest_element_shifting_sticky_box)
	->id()));
	}
	if (constraints.nearest_element_shifting_containing_block) {
	constraints_obj->setNearestLayerShiftingContainingBlock(String::Number(
	FindLayerByElementId(
	root, constraints.nearest_element_shifting_containing_block)
	->id()));
	}

	return constraints_obj;
	}

	static std::unique_ptr<protocol::LayerTree::Layer> BuildObjectForLayer(
	const cc::Layer* root,
	const cc::Layer* layer,
	bool report_wheel_event_listeners) {
	bool using_layer_list =
	RuntimeEnabledFeatures::CompositeAfterPaintEnabled() \|\|
	RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled();

	// When the front-end doesn't show internal layers, it will use the the first
	// DrawsContent layer as the root of the shown layer tree. This doesn't work
	// for layer list because the non-DrawsContent root layer is the parent of
	// all DrawsContent layers. We have to cheat the front-end by setting
	// drawsContent to true for the root layer.
	bool draws_content =
	(using_layer_list && root == layer) \|\| layer->DrawsContent();

	std::unique_ptr<protocol::LayerTree::Layer> layer_object =
	protocol::LayerTree::Layer::create()
	.setLayerId(IdForLayer(layer))
	.setOffsetX(using_layer_list ? 0 : layer->position().x())
	.setOffsetY(using_layer_list ? 0 : layer->position().y())
	.setWidth(layer->bounds().width())
	.setHeight(layer->bounds().height())
	.setPaintCount(layer->paint_count())
	.setDrawsContent(draws_content)
	.build();

	if (auto node_id = layer->owner_node_id())
	layer_object->setBackendNodeId(node_id);

	if (const auto* parent = layer->parent())
	layer_object->setParentLayerId(IdForLayer(parent));

	gfx::Transform transform;
	gfx::Point3F transform_origin;
	if (using_layer_list) {
	transform = layer->ScreenSpaceTransform();
	} else {
	transform = layer->transform();
	transform_origin = layer->transform_origin();
	}

	if (!transform.IsIdentity()) {
	auto transform_array = Array<double>::create();
	for (int col = 0; col < 4; ++col) {
	for (int row = 0; row < 4; ++row)
	transform_array->addItem(transform.matrix().get(row, col));
	}
	layer_object->setTransform(std::move(transform_array));
	// FIXME: rename these to setTransformOrigin*
	if (layer->bounds().width() > 0) {
	layer_object->setAnchorX(transform_origin.x() / layer->bounds().width());
	} else {
	layer_object->setAnchorX(0.f);
	}
	if (layer->bounds().height() > 0) {
	layer_object->setAnchorY(transform_origin.y() / layer->bounds().height());
	} else {
	layer_object->setAnchorY(0.f);
	}
	layer_object->setAnchorZ(transform_origin.z());
	}
	std::unique_ptr<Array<protocol::LayerTree::ScrollRect>> scroll_rects =
	BuildScrollRectsForLayer(layer, report_wheel_event_listeners);
	if (scroll_rects)
	layer_object->setScrollRects(std::move(scroll_rects));
	std::unique_ptr<protocol::LayerTree::StickyPositionConstraint> sticky_info =
	BuildStickyInfoForLayer(root, layer);
	if (sticky_info)
	layer_object->setStickyPositionConstraint(std::move(sticky_info));
	return layer_object;
	}

	InspectorLayerTreeAgent::InspectorLayerTreeAgent(
	InspectedFrames* inspected_frames,
	Client* client)
	: inspected_frames_(inspected_frames),
	client_(client),
	suppress_layer_paint_events_(false) {}

	InspectorLayerTreeAgent::~InspectorLayerTreeAgent() = default;

	void InspectorLayerTreeAgent::Trace(blink::Visitor* visitor) {
	visitor->Trace(inspected_frames_);
	InspectorBaseAgent::Trace(visitor);
	}

	void InspectorLayerTreeAgent::Restore() {
	// We do not re-enable layer agent automatically after navigation. This is
	// because it depends on DOMAgent and node ids in particular, so we let
	// front-end request document and re-enable the agent manually after this.
	}

	Response InspectorLayerTreeAgent::enable() {
	instrumenting_agents_->addInspectorLayerTreeAgent(this);
	Document* document = inspected_frames_->Root()->GetDocument();
	if (!document)
	return Response::Error("The root frame doesn't have document");

	if (RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled() \|\|
	RuntimeEnabledFeatures::CompositeAfterPaintEnabled()) {
	if (document->Lifecycle().GetState() >= DocumentLifecycle::kPaintClean)
	LayerTreePainted();
	} else if (document->Lifecycle().GetState() >=
	DocumentLifecycle::kCompositingClean) {
	LayerTreeDidChange();
	}
	return Response::OK();
	}

	Response InspectorLayerTreeAgent::disable() {
	instrumenting_agents_->removeInspectorLayerTreeAgent(this);
	snapshot_by_id_.clear();
	return Response::OK();
	}

	void InspectorLayerTreeAgent::LayerTreeDidChange() {
	DCHECK(!RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled() &&
	!RuntimeEnabledFeatures::CompositeAfterPaintEnabled());
	GetFrontend()->layerTreeDidChange(BuildLayerTree());
	}

	void InspectorLayerTreeAgent::DidPaint(const cc::Layer* layer,
	const LayoutRect& rect) {
	DCHECK(!RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled() &&
	!RuntimeEnabledFeatures::CompositeAfterPaintEnabled());
	if (suppress_layer_paint_events_)
	return;

	// Should only happen for LocalFrameView paints when compositing is off.
	// Consider different instrumentation method for that.
	if (!layer)
	return;

	std::unique_ptr<protocol::DOM::Rect> dom_rect = protocol::DOM::Rect::create()
	.setX(rect.X())
	.setY(rect.Y())
	.setWidth(rect.Width())
	.setHeight(rect.Height())
	.build();
	GetFrontend()->layerPainted(IdForLayer(layer), std::move(dom_rect));
	}

	void InspectorLayerTreeAgent::LayerTreePainted() {
	DCHECK(RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled() \|\|
	RuntimeEnabledFeatures::CompositeAfterPaintEnabled());

	GetFrontend()->layerTreeDidChange(BuildLayerTree());

	for (const auto& layer :
	inspected_frames_->Root()->View()->RootCcLayer()->children()) {
	if (!layer->update_rect().IsEmpty()) {
	GetFrontend()->layerPainted(IdForLayer(layer.get()),
	BuildObjectForRect(layer->update_rect()));
	}
	}
	}

	std::unique_ptr<Array<protocol::LayerTree::Layer>>
	InspectorLayerTreeAgent::BuildLayerTree() {
	const auto* root_layer = RootLayer();
	if (!root_layer)
	return nullptr;

	std::unique_ptr<Array<protocol::LayerTree::Layer>> layers =
	Array<protocol::LayerTree::Layer>::create();
	auto* root_frame = inspected_frames_->Root();
	auto* layer_for_scrolling =
	root_frame->View()->LayoutViewport()->LayerForScrolling();
	int scrolling_layer_id =
	layer_for_scrolling ? layer_for_scrolling->CcLayer()->id() : 0;
	bool have_blocking_wheel_event_handlers =
	root_frame->GetChromeClient().EventListenerProperties(
	root_frame, cc::EventListenerClass::kMouseWheel) ==
	cc::EventListenerProperties::kBlocking;

	GatherLayers(root_layer, layers, have_blocking_wheel_event_handlers,
	scrolling_layer_id);
	return layers;
	}

	void InspectorLayerTreeAgent::GatherLayers(
	const cc::Layer* layer,
	std::unique_ptr<Array<protocol::LayerTree::Layer>>& layers,
	bool has_wheel_event_handlers,
	int scrolling_layer_id) {
	if (client_->IsInspectorLayer(layer))
	return;
	int layer_id = layer->id();
	layers->addItem(BuildObjectForLayer(
	RootLayer(), layer,
	has_wheel_event_handlers && layer_id == scrolling_layer_id));
	for (auto child : layer->children()) {
	GatherLayers(child.get(), layers, has_wheel_event_handlers,
	scrolling_layer_id);
	}
	}

	const cc::Layer* InspectorLayerTreeAgent::RootLayer() {
	return inspected_frames_->Root()->View()->RootCcLayer();
	}

	static const cc::Layer* FindLayerById(const cc::Layer* root, int layer_id) {
	if (root->id() == layer_id)
	return root;
	for (auto child : root->children()) {
	if (const auto* layer = FindLayerById(child.get(), layer_id))
	return layer;
	}
	return nullptr;
	}

	Response InspectorLayerTreeAgent::LayerById(const String& layer_id,
	const cc::Layer*& result) {
	bool ok;
	int id = layer_id.ToInt(&ok);
	if (!ok)
	return Response::Error("Invalid layer id");

	result = FindLayerById(RootLayer(), id);
	if (!result)
	return Response::Error("No layer matching given id found");
	return Response::OK();
	}

	Response InspectorLayerTreeAgent::compositingReasons(
	const String& layer_id,
	std::unique_ptr<Array<String>>* reason_strings) {
	const cc::Layer* layer = nullptr;
	Response response = LayerById(layer_id, layer);
	if (!response.isSuccess())
	return response;
	CompositingReasons reasons = layer->compositing_reasons();
	*reason_strings = Array<String>::create();
	for (const char* name : CompositingReason::ShortNames(reasons))
	(*reason_strings)->addItem(name);
	return Response::OK();
	}

	Response InspectorLayerTreeAgent::makeSnapshot(const String& layer_id,
	String* snapshot_id) {
	const cc::Layer* layer = nullptr;
	Response response = LayerById(layer_id, layer);
	if (!response.isSuccess())
	return response;
	if (!layer->DrawsContent())
	return Response::Error("Layer does not draw content");

	suppress_layer_paint_events_ = true;

	// If we hit a devtool break point in the middle of document lifecycle, for
	// example, https://crbug.com/788219, this will prevent crash when clicking
	// the "layer" panel.
	if (inspected_frames_->Root()->GetDocument() && inspected_frames_->Root()
	->GetDocument()
	->Lifecycle()
	.LifecyclePostponed())
	return Response::Error("Layer does not draw content");

	inspected_frames_->Root()->View()->UpdateAllLifecyclePhases(
	DocumentLifecycle::LifecycleUpdateReason::kOther);

	suppress_layer_paint_events_ = false;

	auto picture = layer->GetPicture();
	if (!picture)
	return Response::Error("Layer does not produce picture");

	auto snapshot = base::MakeRefCounted<PictureSnapshot>(std::move(picture));
	*snapshot_id = String::Number(++last_snapshot_id_);
	bool new_entry = snapshot_by_id_.insert(*snapshot_id, snapshot).is_new_entry;
	DCHECK(new_entry);
	return Response::OK();
	}

	Response InspectorLayerTreeAgent::loadSnapshot(
	std::unique_ptr<Array<protocol::LayerTree::PictureTile>> tiles,
	String* snapshot_id) {
	if (!tiles->length())
	return Response::Error("Invalid argument, no tiles provided");
	if (tiles->length() > UINT_MAX)
	return Response::Error("Invalid argument, too many tiles provided");
	wtf_size_t tiles_length = static_cast<wtf_size_t>(tiles->length());
	Vector<scoped_refptr<PictureSnapshot::TilePictureStream>> decoded_tiles;
	decoded_tiles.Grow(tiles_length);
	for (wtf_size_t i = 0; i < tiles_length; ++i) {
	protocol::LayerTree::PictureTile* tile = tiles->get(i);
	decoded_tiles[i] = base::AdoptRef(new PictureSnapshot::TilePictureStream());
	decoded_tiles[i]->layer_offset.Set(tile->getX(), tile->getY());
	const protocol::Binary& data = tile->getPicture();
	decoded_tiles[i]->picture =
	SkPicture::MakeFromData(data.data(), data.size());
	}
	scoped_refptr<PictureSnapshot> snapshot =
	PictureSnapshot::Load(decoded_tiles);
	if (!snapshot)
	return Response::Error("Invalid snapshot format");
	if (snapshot->IsEmpty())
	return Response::Error("Empty snapshot");

	*snapshot_id = String::Number(++last_snapshot_id_);
	bool new_entry = snapshot_by_id_.insert(*snapshot_id, snapshot).is_new_entry;
	DCHECK(new_entry);
	return Response::OK();
	}

	Response InspectorLayerTreeAgent::releaseSnapshot(const String& snapshot_id) {
	SnapshotById::iterator it = snapshot_by_id_.find(snapshot_id);
	if (it == snapshot_by_id_.end())
	return Response::Error("Snapshot not found");
	snapshot_by_id_.erase(it);
	return Response::OK();
	}

	Response InspectorLayerTreeAgent::GetSnapshotById(
	const String& snapshot_id,
	const PictureSnapshot*& result) {
	SnapshotById::iterator it = snapshot_by_id_.find(snapshot_id);
	if (it == snapshot_by_id_.end())
	return Response::Error("Snapshot not found");
	result = it->value.get();
	return Response::OK();
	}

	Response InspectorLayerTreeAgent::replaySnapshot(const String& snapshot_id,
	Maybe<int> from_step,
	Maybe<int> to_step,
	Maybe<double> scale,
	String* data_url) {
	const PictureSnapshot* snapshot = nullptr;
	Response response = GetSnapshotById(snapshot_id, snapshot);
	if (!response.isSuccess())
	return response;
	Vector<char> base64_data = snapshot->Replay(
	from_step.fromMaybe(0), to_step.fromMaybe(0), scale.fromMaybe(1.0));
	if (base64_data.IsEmpty())
	return Response::Error("Image encoding failed");
	static constexpr char kUrlPrefix[] = "data:image/png;base64,";
	StringBuilder url;
	url.ReserveCapacity(sizeof(kUrlPrefix) + base64_data.size());
	url.Append(kUrlPrefix);
	url.Append(base64_data.begin(), base64_data.size());
	*data_url = url.ToString();
	return Response::OK();
	}

	static void ParseRect(protocol::DOM::Rect* object, FloatRect* rect) {
	*rect = FloatRect(object->getX(), object->getY(), object->getWidth(),
	object->getHeight());
	}

	Response InspectorLayerTreeAgent::profileSnapshot(
	const String& snapshot_id,
	Maybe<int> min_repeat_count,
	Maybe<double> min_duration,
	Maybe<protocol::DOM::Rect> clip_rect,
	std::unique_ptr<protocol::Array<protocol::Array<double>>>* out_timings) {
	const PictureSnapshot* snapshot = nullptr;
	Response response = GetSnapshotById(snapshot_id, snapshot);
	if (!response.isSuccess())
	return response;
	FloatRect rect;
	if (clip_rect.isJust())
	ParseRect(clip_rect.fromJust(), &rect);
	auto timings =
	snapshot->Profile(min_repeat_count.fromMaybe(1),
	TimeDelta::FromSecondsD(min_duration.fromMaybe(0)),
	clip_rect.isJust() ? &rect : nullptr);
	*out_timings = Array<Array<double>>::create();
	for (const auto& row : timings) {
	std::unique_ptr<Array<double>> out_row = Array<double>::create();
	for (TimeDelta delta : row)
	out_row->addItem(delta.InSecondsF());
	(*out_timings)->addItem(std::move(out_row));
	}
	return Response::OK();
	}

	Response InspectorLayerTreeAgent::snapshotCommandLog(
	const String& snapshot_id,
	std::unique_ptr<Array<protocol::DictionaryValue>>* command_log) {
	const PictureSnapshot* snapshot = nullptr;
	Response response = GetSnapshotById(snapshot_id, snapshot);
	if (!response.isSuccess())
	return response;
	protocol::ErrorSupport errors;
	std::unique_ptr<protocol::Value> log_value = protocol::StringUtil::parseJSON(
	snapshot->SnapshotCommandLog()->ToJSONString());
	*command_log =
	Array<protocol::DictionaryValue>::fromValue(log_value.get(), &errors);
	if (errors.hasErrors())
	return Response::Error(errors.errors());
	return Response::OK();
	}

	} // namespace blink