Add optional debugging output of what paint chunks go into what layers.

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"
@@ skipping 30 matching lines @@
   WTF_MAKE_NONCOPYABLE(PaintArtifactCompositor);
 
  public:
   ~PaintArtifactCompositor();
 
   static std::unique_ptr<PaintArtifactCompositor> create() {
     return WTF::wrapUnique(new PaintArtifactCompositor());
   }
 
   // Updates the layer tree to match the provided paint artifact.
+  // If |storeDebugInfo| is true, stores detailed debugging information in
+  // the layers that will be output as part of a call to layersAsJSON,
+  // if LayerTreeIncludesDebugInfo is specified.

[wkorman, 2016/12/15 21:36:05]

This read to me as if the debug info will only be stored if storeDebugInfo is
true *and* the LayerTreeIncludesDebugInfo flag is specified. Add parens around
the second part, or could just stay "...detailed debugging info in the layers
for use by layersAsJSON as needed."

[chrishtr, 2016/12/15 22:35:11]

Done.

   void update(
       const PaintArtifact&,
-      RasterInvalidationTrackingMap<const PaintChunk>* paintChunkInvalidations);
+      RasterInvalidationTrackingMap<const PaintChunk>* paintChunkInvalidations,
+      bool storeDebugInfo);
 
   // The root layer of the tree managed by this object.
   cc::Layer* rootLayer() const { return m_rootLayer.get(); }
 
   // Wraps rootLayer(), so that it can be attached as a child of another
   // WebLayer.
   WebLayer* getWebLayer() const { return m_webLayer.get(); }
 
   // Returns extra information recorded during unit tests.
   // While not part of the normal output of this class, this provides a simple
@@ skipping 22 matching lines @@
   // 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(
       const PaintArtifact&,
       const PaintChunk&,
       gfx::Vector2dF& layerOffset,
       Vector<std::unique_ptr<ContentLayerClientImpl>>& newContentLayerClients,
-      RasterInvalidationTracking*);
+      RasterInvalidationTracking*,
+      bool storeDebugInfo);
 
   // 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&);
 
   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;
 };
 
 }  // namespace blink
 
 #endif  // PaintArtifactCompositor_h