MouseWheelEventQueue should respect ScrollBegin/End state from RenderWidgetHost.

content/browser/renderer_host/render_widget_host_impl.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/browser/renderer_host/render_widget_host_impl.h"
 
 #include <math.h>
 
 #include <set>
 #include <tuple>
@@ skipping 1083 matching lines @@
     return;
 
   // TODO(wjmaclean) Remove the code for supporting resending gesture events
   // when WebView transitions to OOPIF and BrowserPlugin is removed.
   // http://crbug.com/533069
   bool* is_in_gesture_scroll =
       gesture_event.source_device ==
               blink::WebGestureDevice::kWebGestureDeviceTouchpad
           ? &is_in_touchpad_gesture_scroll_
           : &is_in_touchscreen_gesture_scroll_;
-  if (gesture_event.GetType() == blink::WebInputEvent::kGestureScrollBegin) {
+  if (gesture_event.GetType() == blink::WebInputEvent::kGestureScrollBegin &&
+      !gesture_event.data.scroll_begin.synthetic) {
     DCHECK(!(*is_in_gesture_scroll));
     *is_in_gesture_scroll = true;
-  } else if (gesture_event.GetType() ==
-                 blink::WebInputEvent::kGestureScrollEnd ||
+  } else if ((gesture_event.GetType() ==
+                  blink::WebInputEvent::kGestureScrollEnd &&
+              !gesture_event.data.scroll_end.synthetic) ||
              gesture_event.GetType() ==
                  blink::WebInputEvent::kGestureFlingStart) {
     // TODO(wjmaclean): Re-enable the following DCHECK once crbug.com/695187
     // is fixed.
     // DCHECK(*is_in_gesture_scroll ||
     //       (gesture_event.type() == blink::WebInputEvent::GestureFlingStart &&
     //        gesture_event.sourceDevice ==
     //            blink::WebGestureDevice::WebGestureDeviceTouchpad));
     *is_in_gesture_scroll = false;
   }
@@ skipping 21 matching lines @@
   input_router_->SendGestureEvent(gesture_with_latency);
 
   if (scroll_update_needs_wrapping) {
     ForwardGestureEventWithLatencyInfo(
         CreateScrollEndForWrapping(gesture_event),
         ui::WebInputEventTraits::CreateLatencyInfoForWebGestureEvent(
             gesture_event));
   }
 }
 
+bool RenderWidgetHostImpl::is_in_gesture_scroll(
+    blink::WebGestureDevice device) {
+  switch (device) {
+    case blink::WebGestureDevice::kWebGestureDeviceTouchpad:
+      return is_in_touchpad_gesture_scroll_;
+    case blink::WebGestureDevice::kWebGestureDeviceTouchscreen:
+      return is_in_touchscreen_gesture_scroll_;
+    default:
+      NOTREACHED();
+      return false;  // Required to keep the compiler happy.
+  }
+}
+
 void RenderWidgetHostImpl::ForwardEmulatedTouchEvent(
       const blink::WebTouchEvent& touch_event) {
   TRACE_EVENT0("input", "RenderWidgetHostImpl::ForwardEmulatedTouchEvent");
   ui::LatencyInfo latency_info(ui::SourceEventType::TOUCH);
   TouchEventWithLatencyInfo touch_with_latency(touch_event, latency_info);
   DispatchInputEventWithLatencyInfo(touch_event, &touch_with_latency.latency);
   input_router_->SendTouchEvent(touch_with_latency);
 }
 
 void RenderWidgetHostImpl::ForwardTouchEventWithLatencyInfo(
@@ skipping 1558 matching lines @@
   RenderProcessHost* rph = GetProcess();
   for (std::vector<IPC::Message>::const_iterator i = messages.begin();
        i != messages.end(); ++i) {
     rph->OnMessageReceived(*i);
     if (i->dispatch_error())
       rph->OnBadMessageReceived(*i);
   }
 }
 
 }  // namespace content