cc: Add mailbox support to ResourceProvider write locks.

cc/raster/zero_copy_raster_buffer_provider.cc

 // Copyright 2013 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.
 
 #include "cc/raster/zero_copy_raster_buffer_provider.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 
@@ skipping 78 matching lines @@
     uint64_t previous_content_id) {
   return base::WrapUnique<RasterBuffer>(
       new RasterBufferImpl(resource_provider_, resource));
 }
 
 void ZeroCopyRasterBufferProvider::ReleaseBufferForRaster(
     std::unique_ptr<RasterBuffer> buffer) {
   // Nothing to do here. RasterBufferImpl destructor cleans up after itself.
 }
 
-void ZeroCopyRasterBufferProvider::OrderingBarrier() {
+bool ZeroCopyRasterBufferProvider::OrderingBarrier() {
   // No need to sync resources as this provider does not use GL context.
+  return true;
 }
 
 ResourceFormat ZeroCopyRasterBufferProvider::GetResourceFormat(
     bool must_support_alpha) const {
   if (resource_provider_->IsResourceFormatSupported(preferred_tile_format_) &&
       (DoesResourceFormatSupportAlpha(preferred_tile_format_) ||
        !must_support_alpha)) {
     return preferred_tile_format_;
   }
 
   return resource_provider_->best_texture_format();
 }
 
 bool ZeroCopyRasterBufferProvider::GetResourceRequiresSwizzle(
     bool must_support_alpha) const {
   return ResourceFormatRequiresSwizzle(GetResourceFormat(must_support_alpha));
 }
 
 void ZeroCopyRasterBufferProvider::Shutdown() {}
 
 }  // namespace cc