Extract content dependency from keyboard code

ui/keyboard/keyboard_constants.cc

Index: ui/keyboard/keyboard_constants.cc
diff --git a/ui/keyboard/keyboard_constants.cc b/ui/keyboard/keyboard_constants.cc
deleted file mode 100644
index b13a604f3d14f7f7d66869a33b8df633c70d28f2..0000000000000000000000000000000000000000
--- a/ui/keyboard/keyboard_constants.cc
+++ /dev/null
@@ -1,12 +0,0 @@
-// 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.
-
-#include "ui/keyboard/keyboard_constants.h"
-
-namespace keyboard {
-
-const char kKeyboardURL[] = "chrome://keyboard";
-const char kKeyboardHost[] = "keyboard";
-
-}  // namespace keyboard