Delay activation/draw on GPU tile work completion

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 7c674d37f9d9c5c7b80b90f556007e563d85de15..ab1038b50c25fd5f24ff731376c9c41842eb4ec4 100644
--- a/cc/raster/gpu_raster_buffer_provider.h
+++ b/cc/raster/gpu_raster_buffer_provider.h
@@ -35,6 +35,10 @@ class CC_EXPORT GpuRasterBufferProvider : public RasterBufferProvider {
   ResourceFormat GetResourceFormat(bool must_support_alpha) const override;
   bool IsResourceSwizzleRequired(bool must_support_alpha) const override;
   bool CanPartialRasterIntoProvidedResource() const override;
+  uint64_t SetReadyToDrawCallback(
+      const ResourceProvider::ResourceIdArray& resource_ids,
+      const base::Callback<void(uint64_t)>& callback,
+      uint64_t pending_callback_id) const override;
   void Shutdown() override;
 
   void PlaybackOnWorkerThread(