Move SpeechRecognizer delegate into its own header file and put it in the content namespace.

content/public/browser/speech_recognizer_delegate.h

+// Copyright (c) 2012 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 CONTENT_PUBLIC_BROWSER_SPEECH_RECOGNIZER_DELEGATE_H_
+#define CONTENT_PUBLIC_BROWSER_SPEECH_RECOGNIZER_DELEGATE_H_
+#pragma once
+
+#include "content/public/common/speech_input_result.h"
+
+namespace content {
+
+// Implemented by the caller to receive recognition events.

[jam, 2012/02/13 17:42:12]

nit: this comment now needs more context, since |caller| doesn't mean anything
here.

[tfarina, 2012/02/13 18:44:17]

Done.

+class SpeechRecognizerDelegate {
+ public:
+  virtual void SetRecognitionResult(int caller_id,
+                                    const SpeechInputResult& result) = 0;
+
+  // Invoked when the first audio packet was received from the audio capture
+  // device.
+  virtual void DidStartReceivingAudio(int caller_id) = 0;
+
+  // Invoked when audio recording stops, either due to the end pointer
+  // detecting silence in user input or if |StopRecording| was called. The
+  // delegate has to wait until |DidCompleteRecognition| is invoked before
+  // destroying the |SpeechRecognizer| object.
+  virtual void DidCompleteRecording(int caller_id) = 0;
+
+  // This is guaranteed to be the last method invoked in the recognition
+  // sequence and the |SpeechRecognizer| object can be freed up if necessary.
+  virtual void DidCompleteRecognition(int caller_id) = 0;
+
+  // Informs that the end pointer has started detecting speech.
+  virtual void DidStartReceivingSpeech(int caller_id) = 0;
+
+  // Informs that the end pointer has stopped detecting speech.
+  virtual void DidStopReceivingSpeech(int caller_id) = 0;
+
+  // Invoked if there was an error while recording or recognizing audio. The
+  // session has already been cancelled when this call is made and the DidXxxx
+  // callbacks will not be issued. It is safe to destroy/release the
+  // |SpeechRecognizer| object while processing this call.
+  virtual void OnRecognizerError(int caller_id, SpeechInputError error) = 0;
+
+  // At the start of recognition, a short amount of audio is recorded to
+  // estimate the environment/background noise and this callback is issued
+  // after that is complete. Typically the delegate brings up any speech
+  // recognition UI once this callback is received.
+  virtual void DidCompleteEnvironmentEstimation(int caller_id) = 0;
+
+  // Informs of a change in the captured audio level, useful if displaying
+  // a microphone volume indicator while recording.
+  // The value of |volume| and |noise_volume| is in the [0.0, 1.0] range.
+  virtual void SetInputVolume(int caller_id,
+                              float volume,
+                              float noise_volume) = 0;
+
+ protected:
+  virtual ~SpeechRecognizerDelegate() {}
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_SPEECH_RECOGNIZER_DELEGATE_H_