Reland of cc: Add mailbox support to ResourceProvider write locks.

cc/test/fake_tile_task_manager.cc

Index: cc/test/fake_tile_task_manager.cc
diff --git a/cc/test/fake_tile_task_manager.cc b/cc/test/fake_tile_task_manager.cc
index cc7019897def8af11f5bb393f5a347bf07848368..044de23ea865a26406a7486ac376f78b482ef0f9 100644
--- a/cc/test/fake_tile_task_manager.cc
+++ b/cc/test/fake_tile_task_manager.cc
@@ -8,13 +8,7 @@
 
 namespace cc {
 
-FakeTileTaskManagerImpl::FakeTileTaskManagerImpl()
-    : raster_buffer_provider_(base::WrapUnique<RasterBufferProvider>(
-          new FakeRasterBufferProviderImpl)) {}
-
-FakeTileTaskManagerImpl::FakeTileTaskManagerImpl(
-    std::unique_ptr<RasterBufferProvider> raster_buffer_provider)
-    : raster_buffer_provider_(std::move(raster_buffer_provider)) {}
+FakeTileTaskManagerImpl::FakeTileTaskManagerImpl() {}
 
 FakeTileTaskManagerImpl::~FakeTileTaskManagerImpl() {
   DCHECK_EQ(0u, completed_tasks_.size());
@@ -42,8 +36,4 @@
 
 void FakeTileTaskManagerImpl::Shutdown() {}
 
-RasterBufferProvider* FakeTileTaskManagerImpl::GetRasterBufferProvider() const {
-  return raster_buffer_provider_.get();
-}
-
 }  // namespace cc