Don't synthesize mousemove events if the mouse cursor is not on the widget

ui/views/widget/widget.h

 // 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.
 
 #ifndef UI_VIEWS_WIDGET_WIDGET_H_
 #define UI_VIEWS_WIDGET_WIDGET_H_
 
 #include <set>
 #include <stack>
 #include <vector>
@@ skipping 909 matching lines @@
 
   // See |is_top_level()| accessor.
   bool is_top_level_;
 
   // Tracks whether native widget has been initialized.
   bool native_widget_initialized_;
 
   // Whether native widget has been destroyed.
   bool native_widget_destroyed_;
 
+  // Whether the mouse cursor is on this widget.
+  bool hovered_;

[oshima, 2015/08/20 08:46:34]

maybe is_mouse_on_widget_ ? I'd defer to sky though.

[yoshiki, 2015/08/20 14:59:02]

Changed the name as for now.

+
   // TODO(beng): Remove NativeWidgetGtk's dependence on these:
   // If true, the mouse is currently down.
   bool is_mouse_button_pressed_;
 
   // True if capture losses should be ignored.
   bool ignore_capture_loss_;
 
   // TODO(beng): Remove NativeWidgetGtk's dependence on these:
   // The following are used to detect duplicate mouse move events and not
   // deliver them. Displaying a window may result in the system generating
@@ skipping 16 matching lines @@
   bool movement_disabled_;
 
   ScopedObserver<ui::NativeTheme, ui::NativeThemeObserver> observer_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(Widget);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_WIDGET_H_