mash: Close system tray bubble on click outside its bounds, part 1

ui/views/widget/root_view.h

Index: ui/views/widget/root_view.h
diff --git a/ui/views/widget/root_view.h b/ui/views/widget/root_view.h
index 58c647fccefb4c89d195fdd1627a73bea6e2eeb6..35e83ad3d064c4a542506becc1afc71c676cf9ab 100644
--- a/ui/views/widget/root_view.h
+++ b/ui/views/widget/root_view.h
@@ -159,6 +159,12 @@ class VIEWS_EXPORT RootView : public View,
       View* view,
       View* sibling) WARN_UNUSED_RESULT;
 
+  // Specialized version of SetMouseHandler(). If |clear_on_release| is true the
+  // mouse handler will be cleared on mouse release, which is the common case
+  // and used for drags. If |clear_on_release| is false then the mouse handler
+  // must be explicitly by calling SetMouseHandler() with null.
+  void SetMouseHandler(View* view, bool clear_on_release);
+
   // Overridden from ui::EventDispatcherDelegate:
   bool CanDispatchToTarget(ui::EventTarget* target) override;
   ui::EventDispatchDetails PreDispatchEvent(ui::EventTarget* target,
@@ -187,9 +193,13 @@ class VIEWS_EXPORT RootView : public View,
   // a double-click lands on the same view as its single-click part.
   View* last_click_handler_;
 
-  // true if mouse_pressed_handler_ has been explicitly set
+  // True if mouse_pressed_handler_ has been explicitly set.
   bool explicit_mouse_handler_;
 
+  // True if mouse_pressed_handler_ should be automatically cleared on mouse
+  // release, as is common during drags.
+  bool clear_mouse_handler_on_release_;
+
   // Last position/flag of a mouse press/drag. Used if capture stops and we need
   // to synthesize a release.
   int last_mouse_event_flags_;