Avoid changing |drag_reverted_| if the drag was already completed on ChromeOS

ash/wm/toplevel_window_event_handler.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 "ash/wm/toplevel_window_event_handler.h"
 
 #include "ash/shell.h"
 #include "ash/wm/resize_shadow_controller.h"
 #include "ash/wm/window_resizer.h"
 #include "ash/wm/window_state.h"
@@ skipping 201 matching lines @@
 
   if (window_resizer_.get() && !in_gesture_drag_)
     return;
 
   if (window_resizer_.get() &&
       window_resizer_->resizer()->GetTarget() != target) {
     return;
   }
 
   if (event->details().touch_points() > 2) {
-    if (window_resizer_.get()) {
-      CompleteDrag(DRAG_COMPLETE);
+    if (CompleteDrag(DRAG_COMPLETE))
       event->StopPropagation();
-    }
     return;
   }
 
   switch (event->type()) {
     case ui::ET_GESTURE_TAP_DOWN: {
       int component = GetWindowComponent(target, *event);
       if (!(WindowResizer::GetBoundsChangeForWindowComponent(component) &
             WindowResizer::kBoundsChange_Resizes))
         return;
       ResizeShadowController* controller =
@@ skipping 203 matching lines @@
   if (!resizer)
     return false;
 
   window_resizer_.reset(new ScopedWindowResizer(this, resizer));
 
   pre_drag_window_bounds_ = window->bounds();
   in_gesture_drag_ = (source == aura::client::WINDOW_MOVE_SOURCE_TOUCH);
   return true;
 }
 
-void ToplevelWindowEventHandler::CompleteDrag(DragCompletionStatus status) {
+bool ToplevelWindowEventHandler::CompleteDrag(DragCompletionStatus status) {
+  if (!window_resizer_)
+    return false;
+
   scoped_ptr<ScopedWindowResizer> resizer(window_resizer_.release());
-  if (resizer) {
-    if (status == DRAG_COMPLETE)
+  switch (status) {
+    case DRAG_COMPLETE:
       resizer->resizer()->CompleteDrag();
-    else
+      break;
+    case DRAG_REVERT:
       resizer->resizer()->RevertDrag();
+      break;
+    case DRAG_RESIZER_WINDOW_DESTROYED:
+      // We explicitly do not invoke RevertDrag() since that may do things to
+      // WindowResizer::GetTarget() which was destroyed.
+      break;
   }
   drag_reverted_ = (status == DRAG_REVERT);
 
   first_finger_hittest_ = HTNOWHERE;
   in_gesture_drag_ = false;
   if (in_move_loop_)
     quit_closure_.Run();
+  return true;
 }
 
 void ToplevelWindowEventHandler::HandleMousePressed(
     aura::Window* target,
     ui::MouseEvent* event) {
   if (event->phase() != ui::EP_PRETARGET || !target->delegate())
     return;
 
   // We also update the current window component here because for the
   // mouse-drag-release-press case, where the mouse is released and
@@ skipping 14 matching lines @@
     CompleteDrag(DRAG_COMPLETE);
   }
 }
 
 void ToplevelWindowEventHandler::HandleMouseReleased(
     aura::Window* target,
     ui::MouseEvent* event) {
   if (event->phase() != ui::EP_PRETARGET)
     return;
 
-  if (window_resizer_) {
-    CompleteDrag(event->type() == ui::ET_MOUSE_RELEASED ?
-                     DRAG_COMPLETE : DRAG_REVERT);
-  }
-
-  // Completing the drag may result in hiding the window. If this happens
-  // mark the event as handled so no other handlers/observers act upon the
-  // event. They should see the event on a hidden window, to determine targets
-  // of destructive actions such as hiding. They should not act upon them.
-  if (window_resizer_ &&
-      event->type() == ui::ET_MOUSE_CAPTURE_CHANGED &&
-      !target->IsVisible()) {
-    event->SetHandled();

[sky, 2014/07/09 20:27:02]

Why is marking the event has handled no longer necessary?

[pkotwicz, 2014/07/10 00:23:52]

I couldn't find a case where not handling ui::ET_MOUSE_CAPTURE_CHANGED caused
problems.

This if statement has been a no-op since M34 and there have not been any bug
reports wrt to it being a no-op.

-  }
+  CompleteDrag(event->type() == ui::ET_MOUSE_RELEASED ?
+                   DRAG_COMPLETE : DRAG_REVERT);
 }
 
 void ToplevelWindowEventHandler::HandleDrag(
     aura::Window* target,
     ui::LocatedEvent* event) {
   // This function only be triggered to move window
   // by mouse drag or touch move event.
   DCHECK(event->type() == ui::ET_MOUSE_DRAGGED ||
          event->type() == ui::ET_TOUCH_MOVED ||
          event->type() == ui::ET_GESTURE_SCROLL_UPDATE);
@@ skipping 83 matching lines @@
         const wm::WMEvent event(wm::WM_EVENT_SNAP_RIGHT);
         window_state->OnWMEvent(&event);
       }
       break;
     default:
       NOTREACHED();
   }
 }
 
 void ToplevelWindowEventHandler::ResizerWindowDestroyed() {
-  // We explicitly don't invoke RevertDrag() since that may do things to window.
-  // Instead we destroy the resizer.
-  window_resizer_.reset();
-
-  CompleteDrag(DRAG_REVERT);
+  CompleteDrag(DRAG_RESIZER_WINDOW_DESTROYED);
 }
 
 }  // namespace ash