Unify Android Webview and Chrome's fling

android_webview/browser/browser_view_renderer.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ANDROID_WEBVIEW_BROWSER_BROWSER_VIEW_RENDERER_H_
 #define ANDROID_WEBVIEW_BROWSER_BROWSER_VIEW_RENDERER_H_
 
 #include "android_webview/browser/parent_compositor_draw_constraints.h"
 #include "android_webview/browser/shared_renderer_state.h"
 #include "base/callback.h"
@@ skipping 56 matching lines @@
 
   void SetOffscreenPreRaster(bool enabled);
 
   // View update notifications.
   void SetIsPaused(bool paused);
   void SetViewVisibility(bool visible);
   void SetWindowVisibility(bool visible);
   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);
   float dip_scale() const { return dip_scale_; }
 
   // Set the root layer scroll offset to |new_value|.
   void ScrollTo(gfx::Vector2d new_value);
 
   // Android views hierarchy gluing.
   bool IsVisible() const;
@@ skipping 12 matching lines @@
       content::SynchronousCompositor* compositor) override;
   void PostInvalidate() override;
   void DidUpdateContent() override;
   gfx::Vector2dF GetTotalRootLayerScrollOffset() override;
   void UpdateRootLayerState(const gfx::Vector2dF& total_scroll_offset_dip,
                             const gfx::Vector2dF& max_scroll_offset_dip,
                             const gfx::SizeF& scrollable_size_dip,
                             float page_scale_factor,
                             float min_page_scale_factor,
                             float max_page_scale_factor) override;
-  bool IsExternalFlingActive() const override;
+  bool IsExternalScrollActive() const override;
+  void SetNeedsAnimateFling(const AnimationCallback& fling_animation) override;

[jdduke (slow), 2015/05/18 21:18:34]

Let's go ahead and rename this to |SetNeedsAnimateScroll|, |scroll_animation|
and also below |FlushPendingScrollAnimation|.

[hush (inactive), 2015/05/19 18:14:59]

Done.

   void DidOverscroll(gfx::Vector2dF accumulated_overscroll,
                      gfx::Vector2dF latest_overscroll_delta,
                      gfx::Vector2dF current_fling_velocity) override;
 
   void UpdateParentDrawConstraints();
   void DetachFunctorFromView();
 
  private:
   void SetTotalRootLayerScrollOffset(gfx::Vector2dF new_value_dip);
   bool CanOnDraw();
@@ skipping 17 matching lines @@
   // Do this in a two stage tick due to native MessageLoop favors delayed task,
   // so ensure delayed task is inserted only after the draw task returns.
   void PostFallbackTick();
   void FallbackTickFired();
 
   // Force invoke the compositor to run produce a 1x1 software frame that is
   // immediately discarded. This is a hack to force invoke parts of the
   // compositor that are not directly exposed here.
   void ForceFakeCompositeSW();
 
+  // Honor the requested fling animation as contained in
+  // |pending_fling_animation_|.
+  void FlushPendingFlingAnimation(base::TimeTicks animation_time);
+
   gfx::Vector2d max_scroll_offset() const;
 
   void UpdateMemoryPolicy();
 
   // For debug tracing or logging. Return the string representation of this
   // view renderer's state.
   std::string ToString() const;
 
   BrowserViewRendererClient* client_;
   SharedRendererState shared_renderer_state_;
@@ skipping 15 matching lines @@
 
   gfx::Vector2d last_on_draw_scroll_offset_;
   gfx::Rect last_on_draw_global_visible_rect_;
 
   base::CancelableClosure post_fallback_tick_;
   base::CancelableClosure fallback_tick_fired_;
   bool fallback_tick_pending_;
 
   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_;
 
   // Max scroll offset in CSS pixels.
   gfx::Vector2dF max_scroll_offset_dip_;
 
   // Used to prevent rounding errors from accumulating enough to generate
   // visible skew (especially noticeable when scrolling up and down in the same
   // spot over a period of time).
   gfx::Vector2dF overscroll_rounding_error_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserViewRenderer);
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_BROWSER_VIEW_RENDERER_H_