Defer scroll status determination until scrolling has occurred

content/renderer/render_widget.cc

 // Copyright (c) 2012 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/render_widget.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 1061 matching lines @@
     for (size_t i = 0; i < touch_event.touchesLength; ++i) {
       if (touch_event.touches[i].state == WebTouchPoint::StatePressed &&
           HasTouchEventHandlersAt(
               gfx::ToFlooredPoint(touch_event.touches[i].position))) {
         ack_result = INPUT_EVENT_ACK_STATE_NOT_CONSUMED;
         break;
       }
     }
   }
 
-  // Unconsumed touchmove acks should never be throttled as they're required to
-  // dispatch compositor-handled scroll gestures.
   bool event_type_can_be_rate_limited =
       input_event->type == WebInputEvent::MouseMove ||
-      input_event->type == WebInputEvent::MouseWheel ||
-      (input_event->type == WebInputEvent::TouchMove &&
-       ack_result == INPUT_EVENT_ACK_STATE_CONSUMED);
+      input_event->type == WebInputEvent::MouseWheel;
 
   bool frame_pending = compositor_ && compositor_->BeginMainFrameRequested();
 
   // If we don't have a fast and accurate HighResNow, we assume the input
   // handlers are heavy and rate limit them.
   bool rate_limiting_wanted = true;
   if (base::TimeTicks::IsHighResNowFastAndReliable()) {
       base::TimeTicks end_time = base::TimeTicks::HighResNow();
       total_input_handling_time_this_frame_ += (end_time - start_time);
       rate_limiting_wanted =
@@ skipping 1147 matching lines @@
 void RenderWidget::RegisterVideoHoleFrame(RenderFrameImpl* frame) {
   video_hole_frames_.AddObserver(frame);
 }
 
 void RenderWidget::UnregisterVideoHoleFrame(RenderFrameImpl* frame) {
   video_hole_frames_.RemoveObserver(frame);
 }
 #endif  // defined(VIDEO_HOLE)
 
 }  // namespace content