Refactoring of chrome speech recognition architecture (CL1.2)

content/public/browser/speech_recognition_event_listener.h

Index: content/public/browser/speech_recognition_event_listener.h
diff --git a/content/public/browser/speech_recognition_event_listener.h b/content/public/browser/speech_recognition_event_listener.h
new file mode 100644
index 0000000000000000000000000000000000000000..50fdc808fdd78be3a8cce3e618262dc2e841abcc
--- /dev/null
+++ b/content/public/browser/speech_recognition_event_listener.h
@@ -0,0 +1,67 @@
+// 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_RECOGNITION_EVENT_LISTENER_H_
+#define CONTENT_PUBLIC_BROWSER_SPEECH_RECOGNITION_EVENT_LISTENER_H_
+
+#include "base/basictypes.h"
+#include "content/common/content_export.h"
+#include "content/public/common/speech_recognition_result.h"
+
+namespace content {
+
+// The interface to be implemented by consumers interested in receiving
+// speech recognition events.
+class CONTENT_EXPORT SpeechRecognitionEventListener {
+ public:
+  // Invoked when the StartRequest is received and the recognition process is
+  // started.
+  virtual void OnRecognitionStart(int caller_id_id) = 0;
+
+  // Invoked when the first audio capture is initiated.
+  virtual void OnAudioStart(int caller_id) = 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 OnEnvironmentEstimationComplete(int caller_id) = 0;
+
+  // Informs that the end pointer has started detecting sound (possibly speech).
+  virtual void OnSoundStart(int caller_id) = 0;
+
+  // Informs that the end pointer has stopped detecting sound (a long silence).
+  virtual void OnSoundEnd(int caller_id) = 0;
+
+  // Invoked when audio capture stops, either due to the end pointer detecting
+  // silence, an internal error, or an explicit stop was issued.
+  virtual void OnAudioEnd(int caller_id) = 0;
+
+  // Invoked when a result is retrieved.
+  virtual void OnRecognitionResult(int caller_id,
+                                   const SpeechRecognitionResult& result) = 0;
+
+  // Invoked if there was an error while capturing or recognizing audio.
+  // The recognition has already been cancelled when this call is made and
+  // no more events will be raised.
+  virtual void OnRecognitionError(int caller_id,
+                                  const SpeechRecognitionErrorCode& error) = 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 OnAudioLevelsChange(int caller_id, float volume,
+                                   float noise_volume) = 0;
+
+  // This is guaranteed to be the last event raised in the recognition
+  // process and the |SpeechRecognizer| object can be freed if necessary.
+  virtual void OnRecognitionEnd(int caller_id) = 0;
+
+protected:
+  virtual ~SpeechRecognitionEventListener() { }
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_SPEECH_RECOGNITION_EVENT_LISTENER_H_