Make DrawingBuffer and Canvas2DLayerBridge be cc::TextureLayerClients.

content/renderer/renderer_blink_platform_impl.cc

Index: content/renderer/renderer_blink_platform_impl.cc
diff --git a/content/renderer/renderer_blink_platform_impl.cc b/content/renderer/renderer_blink_platform_impl.cc
index 0cdfd84b860aa2141b9548c5541986068d8dcc8a..74c3a3f564c1ce61651306e8b94893bf430206ed 100644
--- a/content/renderer/renderer_blink_platform_impl.cc
+++ b/content/renderer/renderer_blink_platform_impl.cc
@@ -23,6 +23,7 @@
 #include "build/build_config.h"
 #include "components/url_formatter/url_formatter.h"
 #include "content/child/blob_storage/webblobregistry_impl.h"
+#include "content/child/child_shared_bitmap_manager.h"
 #include "content/child/database_util.h"
 #include "content/child/file_info_util.h"
 #include "content/child/fileapi/webfilesystem_impl.h"
@@ -1131,6 +1132,15 @@ RendererBlinkPlatformImpl::createSharedOffscreenGraphicsContext3DProvider() {
 
 //------------------------------------------------------------------------------
 
+std::unique_ptr<cc::SharedBitmap>
+RendererBlinkPlatformImpl::allocateSharedBitmap(const blink::WebSize& size) {
+  return ChildThreadImpl::current()
+      ->shared_bitmap_manager()
+      ->AllocateSharedBitmap(gfx::Size(size.width, size.height));
+}
+
+//------------------------------------------------------------------------------
+
 blink::WebCompositorSupport* RendererBlinkPlatformImpl::compositorSupport() {
   return &compositor_support_;
 }