Add debug shortcuts that toggles options to shows paint rects

ash/debug.h

Index: ash/debug.h
diff --git a/ash/debug.h b/ash/debug.h
new file mode 100644
index 0000000000000000000000000000000000000000..8ed7c7a31dddba5768b90968b10dfef7c3738396
--- /dev/null
+++ b/ash/debug.h
@@ -0,0 +1,20 @@
+// Copyright (c) 2013 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 ASH_DEBUG_H_
+#define ASH_DEBUG_H_
+
+#include "ash/ash_export.h"
+
+namespace ash {
+namespace debug {
+
+// Toggles debugging features controlled by
+// cc::LayerTreeDebugState.
+ASH_EXPORT void ToggleShowPaintRects();
+
+}  // debug
+}  // ash
+
+#endif  // ASH_DEBUG_H_