Properly resume scrolling if a fling ends during a suppressed scroll

content/renderer/input/input_handler_proxy.h

 // Copyright 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 CONTENT_RENDERER_INPUT_INPUT_HANDLER_PROXY_H_
 #define CONTENT_RENDERER_INPUT_INPUT_HANDLER_PROXY_H_
 
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 48 matching lines @@
 
  private:
   EventDisposition HandleGestureFling(const blink::WebGestureEvent& event);
 
   // Returns true if the event should be suppressed due to to an active,
   // boost-enabled fling, in which case further processing should cease.
   bool FilterInputEventForFlingBoosting(const blink::WebInputEvent& event);
 
   // Schedule a time in the future after which a boost-enabled fling will
   // terminate without further momentum from the user (see |Animate()|).
-  void FlingBoostExtend(const blink::WebGestureEvent& event);
-
-  // Cancel the current fling and insert a GestureScrollBegin if necessary.
-  void FlingBoostCancelAndResumeScrollingIfNecessary();
+  void ExtendBoostedFlingTimeout(const blink::WebGestureEvent& event);
 
   // Returns true if we scrolled by the increment.
   bool TouchpadFlingScroll(const blink::WebFloatSize& increment);
 
+  // Returns true if we actually had an active fling to cancel, also notifying
+  // the client that the fling has ended. Note that if a boosted fling is active
+  // and suppressing an active scroll sequence, a synthetic GestureScrollBegin
+  // will be injected to resume scrolling.
+  bool CancelCurrentFling();
+
   // Returns true if we actually had an active fling to cancel.
-  bool CancelCurrentFling(bool send_fling_stopped_notification);
+  bool CancelCurrentFlingWithoutNotifyingClient();
 
   scoped_ptr<blink::WebGestureCurve> fling_curve_;
   // Parameters for the active fling animation, stored in case we need to
   // transfer it out later.
   blink::WebActiveWheelFlingParameters fling_parameters_;
 
   InputHandlerProxyClient* client_;
   cc::InputHandler* input_handler_;
 
   // Time at which an active fling should expire due to a deferred cancellation
   // event. A call to |Animate()| after this time will end the fling.
   double deferred_fling_cancel_time_seconds_;
 
   // The last event that extended the lifetime of the boosted fling. If the
   // event was a scroll gesture, a GestureScrollBegin will be inserted if the
-  // fling terminates (via |FlingBoostCancelAndResumeScrollingIfNecessary()|).
+  // fling terminates (via |CancelCurrentFling()|).
   blink::WebGestureEvent last_fling_boost_event_;
 
 #ifndef NDEBUG
   bool expect_scroll_update_end_;
 #endif
   bool gesture_scroll_on_impl_thread_;
   bool gesture_pinch_on_impl_thread_;
   // This is always false when there are no flings on the main thread, but
   // conservative in the sense that we might not be actually flinging when it is
   // true.
@@ skipping 12 matching lines @@
   gfx::Vector2dF current_fling_velocity_;
 
   bool smooth_scroll_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(InputHandlerProxy);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_INPUT_INPUT_HANDLER_PROXY_H_