[Android] Implementation of overscroll effect for Android L

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/auto_reset.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
@@ skipping 637 matching lines @@
     CancelCurrentFling(true);
   }
 }
 
 void InputHandlerProxy::MainThreadHasStoppedFlinging() {
   fling_may_be_active_on_main_thread_ = false;
   client_->DidStopFlinging();
 }
 
 void InputHandlerProxy::DidOverscroll(
+    const gfx::PointF& causal_event_viewport_point,
     const gfx::Vector2dF& accumulated_overscroll,
     const gfx::Vector2dF& latest_overscroll_delta) {
   DCHECK(client_);
 
   TRACE_EVENT2("input",
                "InputHandlerProxy::DidOverscroll",
                "dx",
                latest_overscroll_delta.x(),
                "dy",
                latest_overscroll_delta.y());
 
   DidOverscrollParams params;
   params.accumulated_overscroll = accumulated_overscroll;
   params.latest_overscroll_delta = latest_overscroll_delta;
   params.current_fling_velocity =
       ToClientScrollIncrement(current_fling_velocity_);
+  params.causal_event_viewport_point = causal_event_viewport_point;
 
   if (fling_curve_) {
     static const int kFlingOverscrollThreshold = 1;
     disallow_horizontal_fling_scroll_ |=
         std::abs(params.accumulated_overscroll.x()) >=
         kFlingOverscrollThreshold;
     disallow_vertical_fling_scroll_ |=
         std::abs(params.accumulated_overscroll.y()) >=
         kFlingOverscrollThreshold;
   }
@@ skipping 118 matching lines @@
   // trigger a scroll, e.g., with a trivial time delta between fling updates.
   // Return true in this case to prevent early fling termination.
   if (std::abs(clipped_increment.width) < kScrollEpsilon &&
       std::abs(clipped_increment.height) < kScrollEpsilon)
     return true;
 
   return did_scroll;
 }
 
 }  // namespace content