Introduce EventProcessor::OnEventProcessingStarted()

ui/events/event_processor.cc

Index: ui/events/event_processor.cc
diff --git a/ui/events/event_processor.cc b/ui/events/event_processor.cc
index 25c8c3fae92ca2b74e723fce69ee2fe6792b6c49..ff55dbb997d34d5e81e215f22acaad24840b6ed1 100644
--- a/ui/events/event_processor.cc
+++ b/ui/events/event_processor.cc
@@ -14,7 +14,6 @@ EventDispatchDetails EventProcessor::OnEventFromSource(Event* event) {
   CHECK(root);
   EventTargeter* targeter = root->GetEventTargeter();
   CHECK(targeter);
-  PrepareEventForDispatch(event);
 
   // If |event| is in the process of being dispatched or has already been
   // dispatched, then dispatch a copy of the event instead.
@@ -26,9 +25,10 @@ EventDispatchDetails EventProcessor::OnEventFromSource(Event* event) {
     event_to_dispatch = event_copy.get();
   }
 
-  EventTarget* target = targeter->FindTargetForEvent(root, event_to_dispatch);
   EventDispatchDetails details;
-  while (target) {
+  OnEventProcessingStarted(event_to_dispatch);
+  EventTarget* target = targeter->FindTargetForEvent(root, event_to_dispatch);

[sadrul, 2014/09/16 17:16:53]

You don't need to find the target if you aren't going to dispatch the event.

[tdanderson, 2014/09/23 21:30:27]

Yes, good point... also, FindTargetForEvent() may mutate the event and we don't
want that if we're not going to dispatch. Changed.

+  while (target && !event_to_dispatch->handled()) {
     details = DispatchEvent(target, event_to_dispatch);
 
     if (!dispatch_original_event) {
@@ -51,7 +51,7 @@ EventDispatchDetails EventProcessor::OnEventFromSource(Event* event) {
   return details;
 }
 
-void EventProcessor::PrepareEventForDispatch(Event* event) {
+void EventProcessor::OnEventProcessingStarted(Event* event) {
 }
 
 void EventProcessor::OnEventProcessingFinished(Event* event) {