Forward GestureFlingStart in OOPIF, re-enable DCHECK.

content/browser/renderer_host/render_widget_host_input_event_router.cc

 // Copyright 2015 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_input_event_router.h"
 
 #include <vector>
 
 #include "base/metrics/histogram_macros.h"
 #include "cc/quads/surface_draw_quad.h"
@@ skipping 538 matching lines @@
 void RenderWidgetHostInputEventRouter::BubbleScrollEvent(
     RenderWidgetHostViewBase* target_view,
     const blink::WebGestureEvent& event) {
   // TODO(kenrb, tdresser): This needs to be refactored when scroll latching
   // is implemented (see https://crbug.com/526463). This design has some
   // race problems that can result in lost scroll delta, which are very
   // difficult to resolve until this is changed to do all scroll targeting,
   // including bubbling, based on GestureScrollBegin.
   DCHECK(target_view);
   DCHECK(event.GetType() == blink::WebInputEvent::kGestureScrollUpdate ||
-         event.GetType() == blink::WebInputEvent::kGestureScrollEnd);
+         event.GetType() == blink::WebInputEvent::kGestureScrollEnd ||
+         event.GetType() == blink::WebInputEvent::kGestureFlingStart);
   // DCHECK_XNOR the current and original bubble targets. Both should be set
   // if a bubbling gesture scroll is in progress.
   DCHECK(!first_bubbling_scroll_target_.target ==
          !bubbling_gesture_scroll_target_.target);
 
   ui::LatencyInfo latency_info =
       ui::WebInputEventTraits::CreateLatencyInfoForWebGestureEvent(event);
 
   // If target_view is already set up for bubbled scrolls, we forward
   // the event to the current scroll target without further consideration.
   if (target_view == first_bubbling_scroll_target_.target) {
     bubbling_gesture_scroll_target_.target->ProcessGestureEvent(event,
                                                                 latency_info);
-    if (event.GetType() == blink::WebInputEvent::kGestureScrollEnd) {
+    if (event.GetType() == blink::WebInputEvent::kGestureScrollEnd ||
+        event.GetType() == blink::WebInputEvent::kGestureFlingStart) {
       first_bubbling_scroll_target_.target = nullptr;
       bubbling_gesture_scroll_target_.target = nullptr;
     }
     return;
   }
 
   // Disregard GestureScrollEnd events going to non-current targets.
   // These should only happen on ACKs of synthesized GSE events that are
   // sent from SendGestureScrollEnd calls, and are not relevant here.
   if (event.GetType() == blink::WebInputEvent::kGestureScrollEnd)
@@ skipping 250 matching lines @@
 std::vector<RenderWidgetHostView*>
 RenderWidgetHostInputEventRouter::GetRenderWidgetHostViewsForTests() const {
   std::vector<RenderWidgetHostView*> hosts;
   for (auto entry : owner_map_)
     hosts.push_back(entry.second);
 
   return hosts;
 }
 
 }  // namespace content