Try to cut down Browser/TabContents header dependencies.

chrome/browser/tab_contents/test_tab_contents.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_BROWSER_TAB_CONTENTS_TEST_TAB_CONTENTS_H_
 #define CHROME_BROWSER_TAB_CONTENTS_TEST_TAB_CONTENTS_H_
 
 #include "chrome/browser/profile.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/notification_registrar.h"
+#include "webkit/glue/webpreferences.h"
 
 class RenderViewHostFactory;
 class TestRenderViewHost;
 
 // Subclass TabContents to ensure it creates TestRenderViewHosts and does
 // not do anything involving views.
 class TestTabContents : public TabContents {
  public:
   // The render view host factory will be passed on to the
   TestTabContents(Profile* profile, SiteInstance* instance);
@@ skipping 35 matching lines @@
   // TestTabContents. The caller owns the returned object.
   virtual TabContents* Clone();
 
   // Set by individual tests.
   bool transition_cross_site;
 
   NotificationRegistrar registrar_;
 };
 
 #endif  // CHROME_BROWSER_TAB_CONTENTS_TEST_TAB_CONTENTS_H_