Adjust cancelabilty of touchmoves that are queued when scroll start occurs

content/renderer/input/main_thread_event_queue_task.h

Index: content/renderer/input/main_thread_event_queue_task.h
diff --git a/content/renderer/input/main_thread_event_queue_task.h b/content/renderer/input/main_thread_event_queue_task.h
index 64fc0ade70d212d9b9fd714f76c97a431d6252af..537093ee9ca7daec3f1a0fb300cecf564d9bbeb0 100644
--- a/content/renderer/input/main_thread_event_queue_task.h
+++ b/content/renderer/input/main_thread_event_queue_task.h
@@ -21,17 +21,19 @@ class MainThreadEventQueueTask {
  public:
   virtual ~MainThreadEventQueueTask() {}
 
-  enum class CoalesceResult {
-    Coalesced,
-    CannotCoalesce,
-    // Keep iterating on the queue looking for a matching event with the
-    // same modality.
-    KeepSearching,
+  enum class NotifyResult {
+    CoalescedEvent,
+    Stop,
+    KeepIterating,
   };
 
-  virtual CoalesceResult CoalesceWith(const MainThreadEventQueueTask&) = 0;
+  // Notify an event will be queued. Acceptable actions are to coalesce the
+  // event with this event, stop iterating or keep iterating.

[tdresser, 2017/03/31 19:31:02]

This naming is confusing. We aren't notifying an event will be queued, cause we
might not queue it, we might coalesce it. It also isn't really clear from the
comment what it means to keep iterating here.

[dtapuska, 2017/03/31 20:18:18]

I adjusted the names a bit

+  virtual NotifyResult NotifyEventWillBeQueued(
+      const MainThreadEventQueueTask&) = 0;
   virtual bool IsWebInputEvent() const = 0;
   virtual void Dispatch(int routing_id, MainThreadEventQueueClient*) = 0;
+
   virtual void EventHandled(
       int routing_id,
       blink::scheduler::RendererScheduler* renderer_scheduler,