ui: Cache the output of View::OnPaint when the View isn't invalid.

ui/views/view.h

Index: ui/views/view.h
diff --git a/ui/views/view.h b/ui/views/view.h
index 00813e06a7008c5c9b30f9e8ecb867a8c72aaecc..1a56db579bfc1938c7b7737bb0f594d8dc807aec 100644
--- a/ui/views/view.h
+++ b/ui/views/view.h
@@ -24,6 +24,7 @@
 #include "ui/base/ui_base_types.h"
 #include "ui/compositor/layer_delegate.h"
 #include "ui/compositor/layer_owner.h"
+#include "ui/compositor/paint_cache.h"
 #include "ui/events/event.h"
 #include "ui/events/event_target.h"
 #include "ui/gfx/geometry/insets.h"
@@ -1509,6 +1510,9 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
   // Border.
   scoped_ptr<Border> border_;
 
+  // Cached output of painting to be reused in future frames until invalidated.
+  ui::PaintCache paint_cache_;
+
   // RTL painting --------------------------------------------------------------
 
   // Indicates whether or not the gfx::Canvas object passed to View::Paint()