cc: Add mailbox support to ResourceProvider write locks.

cc/raster/one_copy_raster_buffer_provider.h

Index: cc/raster/one_copy_raster_buffer_provider.h
diff --git a/cc/raster/one_copy_raster_buffer_provider.h b/cc/raster/one_copy_raster_buffer_provider.h
index 0c129faa16f78dbc2fcc0efb8162a5cde6154ae8..db00f6b3144a65759b33087bcd35d441773eccf9 100644
--- a/cc/raster/one_copy_raster_buffer_provider.h
+++ b/cc/raster/one_copy_raster_buffer_provider.h
@@ -11,6 +11,7 @@
 #include "cc/output/context_provider.h"
 #include "cc/raster/raster_buffer_provider.h"
 #include "cc/resources/resource_provider.h"
+#include "gpu/command_buffer/common/sync_token.h"
 
 namespace cc {
 struct StagingBuffer;
@@ -28,7 +29,8 @@ class CC_EXPORT OneCopyRasterBufferProvider : public RasterBufferProvider {
       int max_copy_texture_chromium_size,
       bool use_partial_raster,
       int max_staging_buffer_usage_in_bytes,
-      ResourceFormat preferred_tile_format);
+      ResourceFormat preferred_tile_format,
+      bool async_worker_context_enabled);
 
   // Overridden from RasterBufferProvider:
   std::unique_ptr<RasterBuffer> AcquireBufferForRaster(
@@ -59,7 +61,8 @@ class CC_EXPORT OneCopyRasterBufferProvider : public RasterBufferProvider {
                               int max_copy_texture_chromium_size,
                               bool use_partial_raster,
                               int max_staging_buffer_usage_in_bytes,
-                              ResourceFormat preferred_tile_format);
+                              ResourceFormat preferred_tile_format,
+                              bool async_worker_context_enabled);
 
  private:
   void PlaybackToStagingBuffer(
@@ -89,6 +92,9 @@ class CC_EXPORT OneCopyRasterBufferProvider : public RasterBufferProvider {
   ResourceFormat preferred_tile_format_;
   std::unique_ptr<StagingBufferPool> staging_pool_;
 
+  bool async_worker_context_enabled_;
+  gpu::SyncToken sync_token_;
+
   DISALLOW_COPY_AND_ASSIGN(OneCopyRasterBufferProvider);
 };