Implement native speech recognition for the launcher.

chrome/browser/ui/app_list/speech_recognizer_delegate.h

+// Copyright 2014 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_UI_APP_LIST_SPEECH_RECOGNIZER_DELEGATE_H_
+#define CHROME_BROWSER_UI_APP_LIST_SPEECH_RECOGNIZER_DELEGATE_H_
+
+#include <stdint.h>
+
+#include "base/strings/string16.h"
+#include "ui/app_list/speech_ui_model_observer.h"
+
+namespace content {
+class WebContents;
+}
+
+namespace app_list {
+
+// Delegate for the app list speech recognizer. All methods are called from the
+// UI thread.
+class SpeechRecognizerDelegate {
+ public:
+  // Receive a speech recognition result. |is_final| indicated whether the
+  // result is an intermediate or final result. If |is_final| is true, then the
+  // recognizer stops and no more results will be returned.
+  virtual void OnSpeechResult(const base::string16& query, bool is_final) = 0;
+
+  // Invoked regularly to indicate the average sound volume.
+  virtual void OnSpeechSoundLevelChanged(int16_t level) = 0;
+
+  // Invoked when the state of speech recognition is changed.
+  virtual void OnSpeechRecognitionStateChanged(
+      SpeechRecognitionState new_state) = 0;
+
+  // Return a WebContents that is whitelisted to use the speech recognizer.
+  // TODO(amistry): This is an implementation detail that shouldn't be
+  // necessary. Somehow, eliminate this dependency.
+  virtual content::WebContents* GetSpeechContents() = 0;
+
+ protected:
+  virtual ~SpeechRecognizerDelegate() {}
+};
+
+}  // namespace app_list
+
+#endif  // CHROME_BROWSER_UI_APP_LIST_SPEECH_RECOGNIZER_DELEGATE_H_