Do not dispatch gesture events to disabled views

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 621 matching lines @@
   return &drag_info_;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // RootView, private:
 
 // Input -----------------------------------------------------------------------
 
 void RootView::DispatchGestureEvent(ui::GestureEvent* event) {
   if (gesture_handler_) {
-    // |gesture_handler_| can be deleted during processing. In particular, it
-    // will be set to NULL if the view is deleted or removed from the tree as
-    // a result of an event dispatch.
-    ui::GestureEvent handler_event(*event,
-                                   static_cast<View*>(this),
-                                   gesture_handler_);
-    ui::EventDispatchDetails dispatch_details =
-        DispatchEvent(gesture_handler_, &handler_event);
-    if (dispatch_details.dispatcher_destroyed)
-      return;
+    if (gesture_handler_->enabled()) {
+      // |gesture_handler_| can be deleted during processing. In particular, it
+      // will be set to NULL if the view is deleted or removed from the tree as
+      // a result of an event dispatch.
+      ui::GestureEvent handler_event(*event,
+                                     static_cast<View*>(this),
+                                     gesture_handler_);
+      ui::EventDispatchDetails dispatch_details =
+          DispatchEvent(gesture_handler_, &handler_event);
+      if (dispatch_details.dispatcher_destroyed)
+        return;
+
+      if (handler_event.stopped_propagation())
+        event->StopPropagation();
+      else if (handler_event.handled())
+        event->SetHandled();
+    } else {
+      // Disabled views are permitted to be targets of gesture events, but
+      // gesture events should never actually be dispatched to them.
+      event->SetHandled();
+    }
 
     if (event->type() == ui::ET_GESTURE_END) {
       DCHECK_EQ(1, event->details().touch_points());
       // In case a drag was in progress, reset all the handlers. Otherwise, just
       // reset the gesture handler.
       if (gesture_handler_ == mouse_pressed_handler_)
         SetMouseHandler(NULL);
       else
         gesture_handler_ = NULL;
     }
 
-    if (handler_event.stopped_propagation()) {
-      event->StopPropagation();
+    if (event->handled())
       return;
-    } else if (handler_event.handled()) {
-      event->SetHandled();
-      return;
-    }
 
     if (event->type() == ui::ET_GESTURE_SCROLL_BEGIN) {
       // Some view started processing gesture events, however it does not
       // process scroll-gesture events. In such case, we allow the event to
       // bubble up. |gesture_handler_| is changed to its nearest ancestor
       // that handles scroll-gesture events.
       for (gesture_handler_ = gesture_handler_->parent();
            gesture_handler_ && gesture_handler_ != this;
            gesture_handler_ = gesture_handler_->parent()) {
         ui::GestureEvent gesture_event(*event,
@@ skipping 28 matching lines @@
     touch_rect.Offset(-touch_rect.width() / 2, -touch_rect.height() / 2);
     gesture_handler = GetEventHandlerForRect(touch_rect);
   } else {
     gesture_handler = GetEventHandlerForPoint(event->location());
   }
 
   // Walk up the tree until we find a view that wants the gesture event.
   for (gesture_handler_ = gesture_handler;
        gesture_handler_ && (gesture_handler_ != this);
        gesture_handler_ = gesture_handler_->parent()) {
-    // Disabled views eat events but are treated as not handled.
-    if (!gesture_handler_->enabled())
+    // Disabled views are permitted to be targets of gesture events, but
+    // gesture events should never actually be dispatched to them.
+    if (!gesture_handler_->enabled()) {
+      event->SetHandled();
+
+      // Last ui::ET_GESTURE_END should not set the gesture_handler_.
+      if (event->type() == ui::ET_GESTURE_END) {
+        DCHECK_EQ(1, event->details().touch_points());
+        gesture_handler_ = NULL;
+      }
+
       return;
+    }
 
     // See if this view wants to handle the Gesture.
     ui::GestureEvent gesture_event(*event,
                                    static_cast<View*>(this),
                                    gesture_handler_);
     ui::EventDispatchDetails dispatch_details =
         DispatchEvent(gesture_handler_, &gesture_event);
     if (dispatch_details.dispatcher_destroyed)
       return;
 
@@ skipping 80 matching lines @@
 
 #ifndef NDEBUG
   DCHECK(!event_dispatch_target_ || Contains(event_dispatch_target_));
 #endif
 
   return details;
 }
 
 }  // namespace internal
 }  // namespace views