Extract content dependency from keyboard code

ui/keyboard/content/keyboard_constants.h

Index: ui/keyboard/content/keyboard_constants.h
diff --git a/ui/keyboard/keyboard_constants.h b/ui/keyboard/content/keyboard_constants.h
similarity index 63%
rename from ui/keyboard/keyboard_constants.h
rename to ui/keyboard/content/keyboard_constants.h
index 75607c1ee63e717948ddd916f6eddf47736629bb..6c4e6612b11b2ee050b9f88546c7fd3d27ead8c5 100644
--- a/ui/keyboard/keyboard_constants.h
+++ b/ui/keyboard/content/keyboard_constants.h
@@ -1,9 +1,9 @@
-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Copyright 2015 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 UI_KEYBOARD_KEYBOARD_CONSTANTS_H_
-#define UI_KEYBOARD_KEYBOARD_CONSTANTS_H_
+#ifndef UI_KEYBOARD_CONTENT_KEYBOARD_CONSTANTS_H_
+#define UI_KEYBOARD_CONTENT_KEYBOARD_CONSTANTS_H_
 
 #include "ui/keyboard/keyboard_export.h"
 
@@ -17,4 +17,4 @@ KEYBOARD_EXPORT extern const char kKeyboardHost[];
 
 }  // namespace keyboard
 
-#endif  //  UI_KEYBOARD_KEYBOARD_CONSTANTS_H_
+#endif  //  UI_KEYBOARD_CONTENT_KEYBOARD_CONSTANTS_H_