Implement merging non-composited paint property nodes in the PACompositor.

third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.h

 // Copyright 2015 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.
 
 #ifndef PaintArtifactCompositor_h
 #define PaintArtifactCompositor_h
 
 #include "base/memory/ref_counted.h"
 #include "platform/PlatformExport.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/GraphicsLayerClient.h"
 #include "platform/graphics/paint/PaintController.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/PtrUtil.h"
 #include "wtf/Vector.h"
 #include <memory>
 
 namespace cc {
+class DisplayItemList;
 class Layer;
 }
 
 namespace gfx {
 class Vector2dF;
 }
 
 namespace blink {
 
+class GeometryMapper;
 class JSONObject;
 class PaintArtifact;
 class WebLayer;
 struct PaintChunk;
 
 // Responsible for managing compositing in terms of a PaintArtifact.
 //
 // Owns a subtree of the compositor layer tree, and updates it in response to
 // changes in the paint artifact.
 //
@@ skipping 37 matching lines @@
     return m_extraDataForTesting.get();
   }
 
   void setTracksRasterInvalidations(bool);
   void resetTrackedRasterInvalidations();
   bool hasTrackedRasterInvalidations() const;
 
   std::unique_ptr<JSONObject> layersAsJSON(LayerTreeFlags) const;
 
  private:
+  // A pending layer is a collection of paint chunks that will end up in
+  // the same cc::Layer.
+  struct PendingLayer {
+    PendingLayer(const PaintChunk& firstPaintChunk);
+    void add(const PaintChunk&);
+    FloatRect bounds;
+    Vector<const PaintChunk*> paintChunks;
+    bool knownToBeOpaque;
+    bool backfaceHidden;
+    PropertyTreeState propertyTreeState;
+  };
+
   PaintArtifactCompositor();
 
   class ContentLayerClientImpl;
 
+  // Collects the PaintChunks into groups which will end up in the same
+  // cc layer. This includes testing PaintChunks for "merge" compatibility (e.g.
+  // directly composited property tree states are separately composited)
+  // and overlap testing (PaintChunks that overlap existing PaintLayers they
+  // are not compatible with must be separately composited).
+  void collectPendingLayers(const Vector<PaintChunk>& paintChunks,
+                            Vector<PendingLayer>& pendingLayers,
+                            GeometryMapper&);
+
   // Builds a leaf layer that represents a single paint chunk.
   // Note: cc::Layer API assumes the layer bounds start at (0, 0), but the
   // bounding box of a paint chunk does not necessarily start at (0, 0) (and
   // could even be negative). Internally the generated layer translates the
   // paint chunk to align the bounding box to (0, 0) and return the actual
   // origin of the paint chunk in the |layerOffset| outparam.
-  scoped_refptr<cc::Layer> layerForPaintChunk(
+  scoped_refptr<cc::Layer> compositedLayerForPendingLayer(
       const PaintArtifact&,
-      const PaintChunk&,
+      const PendingLayer&,
       gfx::Vector2dF& layerOffset,
       Vector<std::unique_ptr<ContentLayerClientImpl>>& newContentLayerClients,
-      RasterInvalidationTracking*,
-      bool storeDebugInfo);
+      RasterInvalidationTrackingMap<const PaintChunk>*,
+      bool storeDebugInfo,
+      GeometryMapper&);
 
   // Finds a client among the current vector of clients that matches the paint
   // chunk's id, or otherwise allocates a new one.
   std::unique_ptr<ContentLayerClientImpl> clientForPaintChunk(
       const PaintChunk&,
       const PaintArtifact&);
 
+  // This method is an implementation of Algorithm step 4 from goo.gl/6xP8Oe.
+  static scoped_refptr<cc::DisplayItemList> recordPendingLayer(
+      const PaintArtifact&,
+      const PendingLayer&,
+      const gfx::Rect& combinedBounds,
+      GeometryMapper&);
+
+  static bool canMergeInto(const PaintChunk& newChunk,
+                           const PendingLayer& candidatePendingLayer);
+
+  // Returns true if |newChunk| overlaps |candidatePendingLayer| in the
+  // root property tree space.
+  static bool overlaps(const PaintChunk& newChunk,
+                       const PendingLayer& candidatePendingLayer,
+                       GeometryMapper&);
+
   scoped_refptr<cc::Layer> m_rootLayer;
   std::unique_ptr<WebLayer> m_webLayer;
   Vector<std::unique_ptr<ContentLayerClientImpl>> m_contentLayerClients;
 
   bool m_extraDataForTestingEnabled = false;
   std::unique_ptr<ExtraDataForTesting> m_extraDataForTesting;
   friend class StubChromeClientForSPv2;
 
   bool m_isTrackingRasterInvalidations;
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           MergeSimpleChunks);
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           Merge2DTransform);
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           MergeClip);
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           MergeOpacity);
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           MergeNested);
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           ClipPushedUp);
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           EffectPushedUp);
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           EffectAndClipPushedUp);
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           ClipAndEffectNoTransform);
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           TwoClips);
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           TwoEffects);
+
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           PendingLayer);
 };
 
 }  // namespace blink
 
 #endif  // PaintArtifactCompositor_h