cc: Re-enable GPU rasterization after content veto.

cc/trees/layer_tree_host.h

 // Copyright 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.
 
 #ifndef CC_TREES_LAYER_TREE_HOST_H_
 #define CC_TREES_LAYER_TREE_HOST_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 472 matching lines @@
 
   MicroBenchmarkController micro_benchmark_controller_;
 
   void OnCommitForSwapPromises();
 
   void RecordGpuRasterizationHistogram();
 
  private:
   friend class LayerTreeHostSerializationTest;
 
+  // Maximum amount of times to re-enable gpu rasterization after it's been
+  // turned off due to content.
+  enum { kMaxTimesToEnableGpuRasterization = 5 };

[enne (OOO), 2016/06/30 01:02:24]

Why do you want to have a limit on how many times you reeanble? If you have some
long running page that changes state, I feel like we should change an indefinite
number of times?  If you're worried about changing too much, then change the
number of commits you need before swapping?

[ericrk, 2016/06/30 18:46:00]

+1

+  // The number of commits to waitch before attempting to re-enable gpu

[enne (OOO), 2016/06/30 01:02:24]

<_<

+  // rasterization.
+  enum { kFramePeriodToReeanbleGpuRasterization = 10 };

[enne (OOO), 2016/06/30 01:02:24]

Reeanble?

[ericrk, 2016/06/30 18:46:00]

There's a significant cost to switching I'd imagine (re-decode all images,
etc...)... Is 10 frames too little? I'd be more tempted to do this on the order
of at most once a second?

+
   void InitializeProxy(
       std::unique_ptr<Proxy> proxy,
       std::unique_ptr<BeginFrameSource> external_begin_frame_source);
 
   bool DoUpdateLayers(Layer* root_layer);
   void UpdateHudLayer();
 
   bool AnimateLayersRecursive(Layer* current, base::TimeTicks time);
 
   struct UIResourceClientData {
@@ skipping 106 matching lines @@
   LayerIdMap layer_id_map_;
 
   using ElementLayersMap = std::unordered_map<ElementId, Layer*, ElementIdHash>;
   ElementLayersMap element_layers_map_;
 
   // Set of layers that need to push properties.
   std::unordered_set<Layer*> layers_that_should_push_properties_;
 
   uint32_t surface_id_namespace_;
   uint32_t next_surface_sequence_;
+  int num_times_gpu_rasterization_reenabled_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_H_