Cleanup: Remove more forward declarations in various chrome/browser directories.

chrome/browser/speech/speech_input_extension_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_SPEECH_SPEECH_INPUT_EXTENSION_API_H_
 #define CHROME_BROWSER_SPEECH_SPEECH_INPUT_EXTENSION_API_H_
 #pragma once
 
 #include "chrome/browser/extensions/extension_function.h"
 #include "content/public/browser/notification_observer.h"
 
-class SpeechInputExtensionManager;
-
 // Handles asynchronous operations such as starting or stopping speech
 // recognition in the framework of the extension API state machine.
 class SpeechInputAsyncFunction : public AsyncExtensionFunction,
                                  public content::NotificationObserver {
  protected:
   SpeechInputAsyncFunction(int start_state, int transition_state,
                            int end_state, int transition_notification);
   virtual ~SpeechInputAsyncFunction();
 
   virtual void Run() OVERRIDE;
@@ skipping 39 matching lines @@
 };
 
 // Implements experimental.speechInput.isRecording.
 class IsRecordingSpeechInputFunction : public SyncExtensionFunction {
  protected:
   virtual bool RunImpl() OVERRIDE;
   DECLARE_EXTENSION_FUNCTION_NAME("experimental.speechInput.isRecording");
 };
 
 #endif  // CHROME_BROWSER_SPEECH_SPEECH_INPUT_EXTENSION_API_H_