Animated scroll shouldn't consume unhandled scrolls for OOPIFs.

content/renderer/gpu/render_widget_compositor.h

Index: content/renderer/gpu/render_widget_compositor.h
diff --git a/content/renderer/gpu/render_widget_compositor.h b/content/renderer/gpu/render_widget_compositor.h
index 45bab300076f30a7ed665c65d942febed372079a..3248f2aef167501d1b5695f42949c87d9ca425ef 100644
--- a/content/renderer/gpu/render_widget_compositor.h
+++ b/content/renderer/gpu/render_widget_compositor.h
@@ -66,6 +66,7 @@ class CONTENT_EXPORT RenderWidgetCompositor
       const base::CommandLine& cmd,
       CompositorDependencies* compositor_deps,
       float device_scale_factor,
+      bool is_for_subframe,
       const ScreenInfo& screen_info);
   static std::unique_ptr<cc::LayerTreeHost> CreateLayerTreeHost(
       cc::LayerTreeHostClient* client,
@@ -198,6 +199,8 @@ class CONTENT_EXPORT RenderWidgetCompositor
   void DidReceiveCompositorFrameAck() override;
   void DidCompletePageScaleAnimation() override;
 
+  bool IsForSubframe() override;
+
   // cc::LayerTreeHostSingleThreadClient implementation.
   void RequestScheduleAnimation() override;
   void DidSubmitCompositorFrame() override;