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_) {
+    // 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();

[sadrul, 2014/08/15 18:58:52]

the indent here seems off

[tdanderson, 2014/08/15 20:21:50]

Done.

+
+      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;
+      }

[sadrul, 2014/08/15 18:58:52]

Can you combine this block with the code below in lines 671:679? something like:

  if (gesture_handler_->enabled()) {
    <dispatch lines 660:669>
    <update |event| from |handler_event| lines 681:686 without returns>
  } else {
    <mark event handled>
  }

  if (event->type() == END) {
  }

[tdanderson, 2014/08/15 20:21:50]

Done. (I didn't do this originally because the plan is to just rip all of this
code out soon anyway.)

+
+      return;
+    }
+
     // |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;
@@ skipping 56 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