Switch MHTMLGenerationManager to use a Callback.

chrome/browser/extensions/extension_save_page_api.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_EXTENSIONS_EXTENSION_SAVE_PAGE_API_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_SAVE_PAGE_API_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/extensions/extension_function.h"
 #include "content/browser/tab_contents/tab_contents_observer.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
 #include "webkit/blob/deletable_file_reference.h"
 
-class SavePageAsMHTMLFunction : public AsyncExtensionFunction,
-                                public content::NotificationObserver {
+class FilePath;
+
+class SavePageAsMHTMLFunction : public AsyncExtensionFunction {
  public:
   SavePageAsMHTMLFunction();
 
   // Test specific delegate used to test that the temporary file gets deleted.
   class TestDelegate {
    public:
     // Called on the UI thread when the temporary file that contains the
     // generated data has been created.
     virtual void OnTemporaryFileCreated(const FilePath& temp_file) = 0;
   };
   static void SetTestDelegate(TestDelegate* delegate);
 
  private:
   virtual ~SavePageAsMHTMLFunction();
   virtual bool RunImpl() OVERRIDE;
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
   virtual bool OnMessageReceivedFromRenderView(
       const IPC::Message& message) OVERRIDE;
 
   // Called on the file thread.
   void CreateTemporaryFile();
 
   // Called on the UI thread.
   void TemporaryFileCreated(bool success);
   void ReturnFailure(const std::string& error);
   void ReturnSuccess(int64 file_size);
 
+  // Callback called once the MHTML generation is done.
+  void MHTMLGenerated(const FilePath& file_path, int64 mhtml_file_size);
+
   // Returns the TabContents we are associated with, NULL if it's been closed.
   TabContents* GetTabContents();
 
   int tab_id_;
 
   // The path to the temporary file containing the MHTML data.
   FilePath mhtml_path_;
 
   // The file containing the MHTML.
   scoped_refptr<webkit_blob::DeletableFileReference> mhtml_file_;
 
-  content::NotificationRegistrar registrar_;
-
   DECLARE_EXTENSION_FUNCTION_NAME("experimental.savePage.saveAsMHTML")
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SAVE_PAGE_API_H_