Filter GestureFlingStarts with Vx=Vy=0 in RenderWidgetHostViewChildFrame

content/browser/renderer_host/input/input_router_impl.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/browser/renderer_host/input/input_router_impl.h"
 
 #include <math.h>
 
 #include <utility>
 
@@ skipping 411 matching lines @@
     default:
       break;
   }
 
   return consumed;
 }
 
 bool InputRouterImpl::OfferToRenderer(const WebInputEvent& input_event,
                                       const ui::LatencyInfo& latency_info,
                                       InputEventDispatchType dispatch_type) {
+  DCHECK(input_event.type != blink::WebInputEvent::GestureFlingStart ||
+         static_cast<const blink::WebGestureEvent&>(input_event)
+                 .data.flingStart.velocityX != 0.0 ||
+         static_cast<const blink::WebGestureEvent&>(input_event)
+                 .data.flingStart.velocityY != 0.0);
+
   // This conversion is temporary. WebInputEvent should be generated
   // directly from ui::Event with the viewport coordinates. See
   // crbug.com/563730.
   std::unique_ptr<blink::WebInputEvent> event_in_viewport =
       ui::ScaleWebInputEvent(input_event, device_scale_factor_);
   const WebInputEvent* event_to_send =
       event_in_viewport ? event_in_viewport.get() : &input_event;
 
   if (Send(new InputMsg_HandleInputEvent(routing_id(), event_to_send,
                                          latency_info, dispatch_type))) {
@@ skipping 206 matching lines @@
 
   flush_requested_ = false;
   client_->DidFlush();
 }
 
 void InputRouterImpl::SetFrameTreeNodeId(int frameTreeNodeId) {
   frame_tree_node_id_ = frameTreeNodeId;
 }
 
 }  // namespace content