cc: Add mailbox support to ResourceProvider write locks.

cc/raster/gpu_raster_buffer_provider.h

Index: cc/raster/gpu_raster_buffer_provider.h
diff --git a/cc/raster/gpu_raster_buffer_provider.h b/cc/raster/gpu_raster_buffer_provider.h
index 3bbc806d59fe535be0ac26412976755b7d4b94ce..eca5db2367389b5f0ca137642fe882cea0c918e8 100644
--- a/cc/raster/gpu_raster_buffer_provider.h
+++ b/cc/raster/gpu_raster_buffer_provider.h
@@ -9,11 +9,12 @@
 
 #include "base/macros.h"
 #include "cc/raster/raster_buffer_provider.h"
+#include "cc/resources/resource_provider.h"
+#include "gpu/command_buffer/common/sync_token.h"
 
 namespace cc {
 class ContextProvider;
 class GpuRasterizer;
-class ResourceProvider;
 
 class CC_EXPORT GpuRasterBufferProvider : public RasterBufferProvider {
  public:
@@ -23,7 +24,8 @@ class CC_EXPORT GpuRasterBufferProvider : public RasterBufferProvider {
       ContextProvider* context_provider,
       ResourceProvider* resource_provider,
       bool use_distance_field_text,
-      int gpu_rasterization_msaa_sample_count);
+      int gpu_rasterization_msaa_sample_count,
+      bool async_worker_context_enabled);
 
   // Overridden from RasterBufferProvider:
   std::unique_ptr<RasterBuffer> AcquireBufferForRaster(
@@ -36,13 +38,26 @@ class CC_EXPORT GpuRasterBufferProvider : public RasterBufferProvider {
   bool GetResourceRequiresSwizzle(bool must_support_alpha) const override;
   void Shutdown() override;
 
+  void PlaybackOnWorkerThread(
+      ResourceProvider::ScopedWriteLockGr* lock,
+      bool resource_has_previous_content,
+      const RasterSource* raster_source,
+      const gfx::Rect& raster_full_rect,
+      const gfx::Rect& raster_dirty_rect,
+      uint64_t new_content_id,
+      float scale,
+      const RasterSource::PlaybackSettings& playback_settings);
+
  private:
   GpuRasterBufferProvider(ContextProvider* context_provider,
                           ResourceProvider* resource_provider,
                           bool use_distance_field_text,
-                          int gpu_rasterization_msaa_sample_count);
+                          int gpu_rasterization_msaa_sample_count,
+                          bool async_worker_context_enabled);
 
   std::unique_ptr<GpuRasterizer> rasterizer_;
+  bool async_worker_context_enabled_;
+  gpu::SyncToken sync_token_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuRasterBufferProvider);
 };