Revert of Schedule bitmap animation timers on the compositor task runner.

third_party/WebKit/Source/platform/graphics/BitmapImage.h

Index: third_party/WebKit/Source/platform/graphics/BitmapImage.h
diff --git a/third_party/WebKit/Source/platform/graphics/BitmapImage.h b/third_party/WebKit/Source/platform/graphics/BitmapImage.h
index d73e2a742f8ce622c2ca55a01c7420e6d3dda458..902550e29ff617049b0f37bd35373d9e76fd8536 100644
--- a/third_party/WebKit/Source/platform/graphics/BitmapImage.h
+++ b/third_party/WebKit/Source/platform/graphics/BitmapImage.h
@@ -192,7 +192,7 @@ class PLATFORM_EXPORT BitmapImage final : public Image {
       cached_frame_;  // A cached copy of the most recently-accessed frame.
   size_t cached_frame_index_;  // Index of the frame that is cached.
 
-  std::unique_ptr<TaskRunnerTimer<BitmapImage>> frame_timer_;
+  std::unique_ptr<Timer<BitmapImage>> frame_timer_;
 
   ImageAnimationPolicy
       animation_policy_;  // Whether or not we can play animation.
@@ -217,8 +217,6 @@ class PLATFORM_EXPORT BitmapImage final : public Image {
                                      // the next call to startAnimation().
 
   size_t frame_count_;
-
-  RefPtr<WebTaskRunner> task_runner_;
 };
 
 DEFINE_IMAGE_TYPE_CASTS(BitmapImage);