Do not set the last mouse location from synthesized event

ui/aura/root_window.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/aura/root_window.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 380 matching lines @@
     const gfx::Display& display =
         gfx::Screen::GetScreenFor(window())->GetDisplayNearestWindow(window());
     cursor_client->SetDisplay(display);
   }
   synthesize_mouse_move_ = false;
 }
 
 ui::EventDispatchDetails RootWindow::DispatchMouseEnterOrExit(
     const ui::MouseEvent& event,
     ui::EventType type) {
+
+  if (event.type() != ui::ET_MOUSE_CAPTURE_CHANGED &&
+      !(event.flags() & ui::EF_IS_SYNTHESIZED)) {
+    SetLastMouseLocation(window(), event.root_location());
+  }

[oshima, 2014/02/11 19:43:38]

This was necessary because EnterOrExit may cause early exit in 
PreDispatchMouseEvent, which means PreDispatchLocatedEvent is not called. Let me
know if there is a better way/place to fix this.

[sadrul, 2014/02/11 21:26:20]

Can you explain this a bit more? The early returns in PreDispatchMouseEvent for
EnterOrExit: are these only for the cases where the |target| is destroyed
(because I think the rest of the early returns are related to the root-window
itself being destroyed)? If so, can we do this in there instead?

+
   if (!mouse_moved_handler_ || !mouse_moved_handler_->delegate())
     return DispatchDetails();
 
   // |event| may be an event in the process of being dispatched to a target (in
   // which case its locations will be in the event's target's coordinate
   // system), or a synthetic event created in root-window (in which case, the
   // event's target will be NULL, and the event will be in the root-window's
   // coordinate system.
   aura::Window* target = static_cast<Window*>(event.target());
   if (!target)
@@ skipping 375 matching lines @@
 ui::EventDispatchDetails RootWindow::SynthesizeMouseMoveEvent() {
   DispatchDetails details;
   if (!synthesize_mouse_move_)
     return details;
   synthesize_mouse_move_ = false;
   gfx::Point root_mouse_location = GetLastMouseLocationInRoot();
   if (!window()->bounds().Contains(root_mouse_location))
     return details;
   gfx::Point host_mouse_location = root_mouse_location;
   host()->ConvertPointToHost(&host_mouse_location);
-
   ui::MouseEvent event(ui::ET_MOUSE_MOVED,
                        host_mouse_location,
                        host_mouse_location,
                        ui::EF_IS_SYNTHESIZED,
                        0);
   return OnEventFromSource(&event);
 }
 
 void RootWindow::PreDispatchLocatedEvent(Window* target,
                                          ui::LocatedEvent* event) {
   int flags = event->flags();
   if (IsNonClientLocation(target, event->location()))
     flags |= ui::EF_IS_NON_CLIENT;
   event->set_flags(flags);
 
   if (!dispatching_held_event_ &&
       (event->IsMouseEvent() || event->IsScrollEvent())) {
-    if (event->type() != ui::ET_MOUSE_CAPTURE_CHANGED)
-      SetLastMouseLocation(window(), event->root_location());
-    if (!(event->flags() & ui::EF_IS_SYNTHESIZED))
+    if (!(event->flags() & ui::EF_IS_SYNTHESIZED)) {

[sadrul, 2014/02/13 04:38:59]

Merge the two if's?

[oshima, 2014/02/13 15:25:32]

Done.

+      if (event->type() != ui::ET_MOUSE_CAPTURE_CHANGED)
+        SetLastMouseLocation(window(), event->root_location());
       synthesize_mouse_move_ = false;
+    }
   }
 }
 
 void RootWindow::PreDispatchMouseEvent(Window* target,
                                        ui::MouseEvent* event) {
   client::CursorClient* cursor_client = client::GetCursorClient(window());
   if (cursor_client &&
       !cursor_client->IsMouseEventsEnabled() &&
       (event->flags() & ui::EF_IS_SYNTHESIZED)) {
     event->SetHandled();
@@ skipping 113 matching lines @@
       break;
 
     default:
       NOTREACHED();
       break;
   }
   PreDispatchLocatedEvent(target, event);
 }
 
 }  // namespace aura