Refactor menu controller to isolate aura dependency.

ui/aura/env.h

Index: ui/aura/env.h
diff --git a/ui/aura/env.h b/ui/aura/env.h
index 1d6c19de3fb07a4a15b1cab5fd84e714daa09438..2e7d227f8d4cf34a478fa9d20d3e2b4ea184d2b9 100644
--- a/ui/aura/env.h
+++ b/ui/aura/env.h
@@ -39,7 +39,7 @@ class AURA_EXPORT Env : public ui::EventTarget {
   void AddObserver(EnvObserver* observer);
   void RemoveObserver(EnvObserver* observer);
 
-  const int mouse_button_flags() const { return mouse_button_flags_; }

[tapted, 2014/05/02 00:22:57]

yeah - clang warns me about this too... but we shouldn't expose this header to
anything in a non-aura build. All the ui/aura and ui/wm headers should be
avoided completely if !aura. guarding the #includes with #if defined(..) is an
option. But it's ugly.

+  int mouse_button_flags() const { return mouse_button_flags_; }
   void set_mouse_button_flags(int mouse_button_flags) {
     mouse_button_flags_ = mouse_button_flags;
   }