Unify Android Webview and Chrome's fling

android_webview/browser/browser_view_renderer.h

Index: android_webview/browser/browser_view_renderer.h
diff --git a/android_webview/browser/browser_view_renderer.h b/android_webview/browser/browser_view_renderer.h
index 477a039cecc344617fb77a5424e38c8310d498e0..83955ee1552e54887a9e75287b31afda3ea901fb 100644
--- a/android_webview/browser/browser_view_renderer.h
+++ b/android_webview/browser/browser_view_renderer.h
@@ -74,6 +74,7 @@ class BrowserViewRenderer : public content::SynchronousCompositorClient {
   void OnSizeChanged(int width, int height);
   void OnAttachedToWindow(int width, int height);
   void OnDetachedFromWindow();
+  void OnComputeScroll(base::TimeTicks animation_time);
 
   // Sets the scale for logical<->physical pixel conversions.
   void SetDipScale(float dip_scale);
@@ -106,7 +107,9 @@ class BrowserViewRenderer : public content::SynchronousCompositorClient {
                             float page_scale_factor,
                             float min_page_scale_factor,
                             float max_page_scale_factor) override;
-  bool IsExternalFlingActive() const override;
+  bool IsExternalScrollActive() const override;
+  void SetNeedsAnimateScroll(
+      const AnimationCallback& scroll_animation) override;
   void DidOverscroll(gfx::Vector2dF accumulated_overscroll,
                      gfx::Vector2dF latest_overscroll_delta,
                      gfx::Vector2dF current_fling_velocity) override;
@@ -179,6 +182,11 @@ class BrowserViewRenderer : public content::SynchronousCompositorClient {
 
   gfx::Size size_;
 
+  // Used to drive a fling animation as requested by the compositor. This acts
+  // as a single-shot animation; the compositor will continually post an
+  // animation callback as long as they're required.
+  AnimationCallback pending_fling_animation_;
+
   // Current scroll offset in CSS pixels.
   gfx::Vector2dF scroll_offset_dip_;