Move views::Accelerator to ui in order to use it from aura code.

views/view.h

Index: views/view.h
diff --git a/views/view.h b/views/view.h
index 6c49097a8d8d187ae85d087fd1c6d6e727c4485c..bfd075c6a81ad5f046d0c20c35b201c4269110bf 100644
--- a/views/view.h
+++ b/views/view.h
@@ -98,7 +98,7 @@ class RootView;
 //
 /////////////////////////////////////////////////////////////////////////////
 class VIEWS_EXPORT View : public ui::LayerDelegate,
-                          public AcceleratorTarget {
+                          public ui::AcceleratorTarget {
  public:
   typedef std::vector<View*> Views;
 
@@ -645,7 +645,7 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
   virtual void ResetAccelerators();
 
   // Overridden from AcceleratorTarget:
-  virtual bool AcceleratorPressed(const Accelerator& accelerator) OVERRIDE;
+  virtual bool AcceleratorPressed(const ui::Accelerator& accelerator) OVERRIDE;
 
   // Focus ---------------------------------------------------------------------