Remove uses of external begin frame sources

content/test/fake_compositor_dependencies.h

Index: content/test/fake_compositor_dependencies.h
diff --git a/content/test/fake_compositor_dependencies.h b/content/test/fake_compositor_dependencies.h
index 6893ddca282eedcbf42a394274b016af7acf517a..2a6537bbb21dd07b165dfe98c9a9b69707a9452c 100644
--- a/content/test/fake_compositor_dependencies.h
+++ b/content/test/fake_compositor_dependencies.h
@@ -39,8 +39,6 @@ class FakeCompositorDependencies : public CompositorDependencies {
   cc::SharedBitmapManager* GetSharedBitmapManager() override;
   gpu::GpuMemoryBufferManager* GetGpuMemoryBufferManager() override;
   blink::scheduler::RendererScheduler* GetRendererScheduler() override;
-  std::unique_ptr<cc::BeginFrameSource> CreateExternalBeginFrameSource(
-      int routing_id) override;
   cc::ImageSerializationProcessor* GetImageSerializationProcessor() override;
   cc::TaskGraphRunner* GetTaskGraphRunner() override;
   bool AreImageDecodeTasksEnabled() override;