cc: Let skia veto gpu rasterization.

cc/layers/picture_layer.h

 // Copyright 2012 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 CC_LAYERS_PICTURE_LAYER_H_
 #define CC_LAYERS_PICTURE_LAYER_H_
 
 #include "cc/base/invalidation_region.h"
 #include "cc/debug/devtools_instrumentation.h"
 #include "cc/debug/micro_benchmark_controller.h"
@@ skipping 23 matching lines @@
                       const OcclusionTracker<Layer>* occlusion) OVERRIDE;
   virtual void SetIsMask(bool is_mask) OVERRIDE;
   virtual bool SupportsLCDText() const OVERRIDE;
   virtual skia::RefPtr<SkPicture> GetPicture() const OVERRIDE;
 
   virtual void RunMicroBenchmark(MicroBenchmark* benchmark) OVERRIDE;
 
   ContentLayerClient* client() { return client_; }
 
   void SetHasGpuRasterizationHint(bool has_hint);
+  bool ShouldUseGpuRasterization() const;
+
+  PicturePile* GetPicturePileForTesting() const { return pile_.get(); }
 
  protected:
   explicit PictureLayer(ContentLayerClient* client);
   virtual ~PictureLayer();
 
  private:
   ContentLayerClient* client_;
   scoped_refptr<PicturePile> pile_;
   devtools_instrumentation::
       ScopedLayerObjectTracker instrumentation_object_tracker_;
   // Invalidation to use the next time update is called.
   InvalidationRegion pending_invalidation_;
   // Invalidation from the last time update was called.
   Region pile_invalidation_;
   gfx::Rect last_updated_visible_content_rect_;
   bool is_mask_;
-  bool has_gpu_rasterization_hint_;
+
+  enum TriBool { TRIBOOL_UNKNOWN, TRIBOOL_FALSE, TRIBOOL_TRUE };

[enne (OOO), 2014/04/04 18:34:19]

I think this would be clearer if you just added a second bool for
gpu_rasterization_has_ever_been_disabled_.  

Actually, rather than adding a second boolean, could you also use the
PicturePile's suitable boolean as the "sticky" disabled flag directly?

[alokp, 2014/04/04 18:50:34]

I do not understand the comment about PicturePile boolean. Can you elaborate?

[enne (OOO), 2014/04/04 19:40:07]

I'm saying that pile_->is_suitable_for_gpu_rasterization() is already sticky
across frames, and that rather than using a tri-state enum (which I find
confusing in logic), that you can just check that function as a "has ever been
disabled" flag.

+  TriBool has_gpu_rasterization_hint_;
 
   int update_source_frame_number_;
 
   DISALLOW_COPY_AND_ASSIGN(PictureLayer);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_PICTURE_LAYER_H_