Let the browser know the end of fling

content/renderer/input/input_handler_proxy.cc

 // 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.
 
 #include "content/renderer/input/input_handler_proxy.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "content/renderer/input/input_handler_proxy_client.h"
@@ skipping 334 matching lines @@
   } else {
     TRACE_EVENT_INSTANT0("renderer",
                          "InputHandlerProxy::animate::flingOver",
                          TRACE_EVENT_SCOPE_THREAD);
     CancelCurrentFling();
   }
 }
 
 void InputHandlerProxy::MainThreadHasStoppedFlinging() {
   fling_may_be_active_on_main_thread_ = false;
+  client_->DidStopFlinging();

[jdduke (slow), 2014/01/09 20:07:14]

What if there's a fling active on the impl thread?

 }
 
 void InputHandlerProxy::DidOverscroll(const cc::DidOverscrollParams& params) {
   DCHECK(client_);
   if (fling_curve_) {
     static const int kFlingOverscrollThreshold = 1;
     disallow_horizontal_fling_scroll_ |=
         std::abs(params.accumulated_overscroll.x()) >=
         kFlingOverscrollThreshold;
     disallow_vertical_fling_scroll_ |=
@@ skipping 16 matching lines @@
   }
 
   TRACE_EVENT_INSTANT1("renderer",
                        "InputHandlerProxy::CancelCurrentFling",
                        TRACE_EVENT_SCOPE_THREAD,
                        "had_fling_animation",
                        had_fling_animation);
   fling_curve_.reset();
   gesture_scroll_on_impl_thread_ = false;
   fling_parameters_ = blink::WebActiveWheelFlingParameters();
+  client_->DidStopFlinging();

[jdduke (slow), 2014/01/09 20:07:14]

I think we only want to send this if there was a fling curve, no?

[Xianzhu, 2014/01/10 20:16:02]

Done.

   return had_fling_animation;
 }
 
 bool InputHandlerProxy::TouchpadFlingScroll(
     const WebFloatSize& increment) {
   WebMouseWheelEvent synthetic_wheel;
   synthetic_wheel.type = WebInputEvent::MouseWheel;
   synthetic_wheel.deltaX = increment.width;
   synthetic_wheel.deltaY = increment.height;
   synthetic_wheel.hasPreciseScrollingDeltas = true;
@@ skipping 74 matching lines @@
   TRACE_EVENT2("renderer",
                "InputHandlerProxy::notifyCurrentFlingVelocity",
                "vx",
                velocity.width,
                "vy",
                velocity.height);
   input_handler_->NotifyCurrentFlingVelocity(ToClientScrollIncrement(velocity));
 }
 
 }  // namespace content