WebUI: Move the core files of WebUI from chrome/browser/webui to content/webui.

chrome/browser/webui/print_preview_ui.h

 // Copyright (c) 2011 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_WEBUI_PRINT_PREVIEW_UI_H_
 #define CHROME_BROWSER_WEBUI_PRINT_PREVIEW_UI_H_
 #pragma once
 
 #include "base/ref_counted.h"
-#include "chrome/browser/webui/web_ui.h"
+#include "content/browser/webui/web_ui.h"
 
 class PrintPreviewUIHTMLSource;
 
 class PrintPreviewUI : public WebUI {
  public:
   explicit PrintPreviewUI(TabContents* contents);
   virtual ~PrintPreviewUI();
 
   PrintPreviewUIHTMLSource* html_source();
 
   // Notify the Web UI renderer that preview data is available.
   // |expected_pages_count| specifies the total number of pages.
   void PreviewDataIsAvailable(int expected_pages_count);
 
  private:
   scoped_refptr<PrintPreviewUIHTMLSource> html_source_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintPreviewUI);
 };
 
 #endif  // CHROME_BROWSER_WEBUI_PRINT_PREVIEW_UI_H_