Move the remaining files in chrome\common to content\common.

content/common/page_zoom.h

 // Copyright (c) 2009 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 CHROME_COMMON_PAGE_ZOOM_H_
-#define CHROME_COMMON_PAGE_ZOOM_H_
+#ifndef CONTENT_COMMON_PAGE_ZOOM_H_
+#define CONTENT_COMMON_PAGE_ZOOM_H_
 #pragma once
 
 #include "base/basictypes.h"
 
 class PageZoom {
  public:
   // This enum is the parameter to various text/page zoom commands so we know
   // what the specific zoom command is.
   enum Function {
     ZOOM_OUT = -1,
     RESET    = 0,
     ZOOM_IN  = 1,
   };
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PageZoom);
 };
 
-#endif  // CHROME_COMMON_PAGE_ZOOM_H_
+#endif  // CONTENT_COMMON_PAGE_ZOOM_H_