Introduce EventProcessor::OnEventProcessingStarted()

ui/views/widget/root_view.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 "ui/views/widget/root_view.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 231 matching lines @@
   return focus_traversable_parent_view_;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // RootView, ui::EventProcessor overrides:
 
 ui::EventTarget* RootView::GetRootTarget() {
   return this;
 }
 
-ui::EventDispatchDetails RootView::OnEventFromSource(ui::Event* event) {
-  if (event->IsKeyEvent())
-    return EventProcessor::OnEventFromSource(event);
-
-  if (event->IsScrollEvent())
-    return EventProcessor::OnEventFromSource(event);
-
+bool RootView::OnEventProcessingStarted(ui::Event* event) {
   if (event->IsGestureEvent()) {
-    // TODO(tdanderson): Once DispatchGestureEvent() has been removed, move
-    //                   all of this logic into an override of a new
-    //                   virtual method
-    //                   EventProcessor::OnEventProcessingStarted() (which
-    //                   returns false if no processing should take place).
-    //                   Also move the implementation of
-    //                   PrepareEventForDispatch() into this new method.
-    //                   Then RootView::OnEventFromSource() can be removed.
+    gesture_handler_set_before_processing_ = !!gesture_handler_;

[sadrul, 2014/09/15 14:10:36]

Should you move this down so this is set only when returning true?

[tdanderson, 2014/09/15 18:20:26]

With the CL as-is, this will need to stay where it is otherwise the value of
|gesture_handler_set_before_processing_| may be incorrect by the time we reach
OnEventProcessingFinished(), causing |gesture_handler_| to be reset to NULL when
it shouldn't.

If I end up handling the event instead as per your other comment, then I should
be able to move this line.

     ui::GestureEvent* gesture_event = event->AsGestureEvent();
 
-    // Do not dispatch ui::ET_GESTURE_BEGIN events.
+    // Do not process ui::ET_GESTURE_BEGIN events.
     if (gesture_event->type() == ui::ET_GESTURE_BEGIN)
-      return DispatchDetails();
+      return false;
 
-    // Ignore ui::ET_GESTURE_END events which do not correspond to the
+    // Do not process ui::ET_GESTURE_END events which do not correspond to the
     // removal of the final touch point.
     if (gesture_event->type() == ui::ET_GESTURE_END &&
         gesture_event->details().touch_points() > 1) {
-      return DispatchDetails();
+      return false;
     }
 
-    // Ignore subsequent gesture scroll events if no handler was set for a
-    // ui::ET_GESTURE_SCROLL_BEGIN event.
+    // Do not process subsequent gesture scroll events if no handler was set for
+    // a ui::ET_GESTURE_SCROLL_BEGIN event.
     if (!gesture_handler_ &&
         (gesture_event->type() == ui::ET_GESTURE_SCROLL_UPDATE ||
          gesture_event->type() == ui::ET_GESTURE_SCROLL_END ||
          gesture_event->type() == ui::ET_SCROLL_FLING_START)) {
-      return DispatchDetails();
+      return false;
     }
-
-    gesture_handler_set_before_processing_ = !!gesture_handler_;
-    return EventProcessor::OnEventFromSource(event);
   }
 
-  if (event->IsTouchEvent())
-    NOTREACHED() << "Touch events should not be sent to RootView.";
-
-  if (event->IsMouseEvent())
-    NOTREACHED() << "Should not be called with a MouseEvent.";
-
-  return DispatchDetails();
+  return true;
 }
 
 void RootView::OnEventProcessingFinished(ui::Event* event) {
   // If |event| was not handled and |gesture_handler_| was not set by the
   // dispatch of a previous gesture event, then no default gesture handler
   // should be set prior to the next gesture event being received.
   if (event->IsGestureEvent() &&
       !event->handled() &&
       !gesture_handler_set_before_processing_) {
     gesture_handler_ = NULL;
@@ skipping 426 matching lines @@
 
 #ifndef NDEBUG
   DCHECK(!event_dispatch_target_ || Contains(event_dispatch_target_));
 #endif
 
   return details;
 }
 
 }  // namespace internal
 }  // namespace views