Separate out the TtsController interface from it's impl

chrome/browser/speech/tts_controller_impl.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 CHROME_BROWSER_SPEECH_TTS_CONTROLLER_IMPL_H_
+#define CHROME_BROWSER_SPEECH_TTS_CONTROLLER_IMPL_H_
+
+#include <queue>
+#include <set>
+#include <string>
+#include <vector>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/singleton.h"
+#include "base/memory/weak_ptr.h"
+#include "chrome/browser/speech/tts_controller.h"
+#include "url/gurl.h"
+
+// Singleton class that manages text-to-speech for the TTS and TTS engine
+// extension APIs, maintaining a queue of pending utterances and keeping
+// track of all state.
+class TtsControllerImpl : public TtsController {
+ public:
+  // Get the single instance of this class.
+  static TtsControllerImpl* GetInstance();
+
+  virtual bool IsSpeaking() OVERRIDE;

[sky, 2014/07/23 19:23:24]

nit: We generally prefix overrides sections with something like:

// TtsController overrides:

(see chrome style guide for specifics).

+  virtual void SpeakOrEnqueue(Utterance* utterance) OVERRIDE;
+  virtual void Stop() OVERRIDE;
+  virtual void Pause() OVERRIDE;
+  virtual void Resume() OVERRIDE;
+  virtual void OnTtsEvent(int utterance_id,
+                  TtsEventType event_type,
+                  int char_index,
+                  const std::string& error_message) OVERRIDE;
+  virtual void GetVoices(Profile* profile,
+                         std::vector<VoiceData>* out_voices) OVERRIDE;
+  virtual void RetrySpeakingQueuedUtterances() OVERRIDE;
+  virtual void VoicesChanged() OVERRIDE;
+  virtual void AddVoicesChangedDelegate(
+      VoicesChangedDelegate* delegate) OVERRIDE;
+  virtual void RemoveVoicesChangedDelegate(
+      VoicesChangedDelegate* delegate) OVERRIDE;
+  virtual void SetTtsEngineDelegate(TtsEngineDelegate* delegate) OVERRIDE;
+  virtual void SetPlatformImpl(TtsPlatformImpl* platform_impl) OVERRIDE;
+  virtual int QueueSize() OVERRIDE;
+
+ protected:
+  TtsControllerImpl();
+  virtual ~TtsControllerImpl();
+
+ private:
+  // Get the platform TTS implementation (or injected mock).
+  TtsPlatformImpl* GetPlatformImpl();
+
+  // Start speaking the given utterance. Will either take ownership of
+  // |utterance| or delete it if there's an error. Returns true on success.
+  void SpeakNow(Utterance* utterance);
+
+  // Clear the utterance queue. If send_events is true, will send
+  // TTS_EVENT_CANCELLED events on each one.
+  void ClearUtteranceQueue(bool send_events);
+
+  // Finalize and delete the current utterance.
+  void FinishCurrentUtterance();
+
+  // Start speaking the next utterance in the queue.
+  void SpeakNextUtterance();
+
+  // Given an utterance and a vector of voices, return the
+  // index of the voice that best matches the utterance.
+  int GetMatchingVoice(const Utterance* utterance,
+                       std::vector<VoiceData>& voices);
+
+  friend struct DefaultSingletonTraits<TtsControllerImpl>;
+
+  // The current utterance being spoken.
+  Utterance* current_utterance_;
+
+  // Whether the queue is paused or not.
+  bool paused_;
+
+  // A queue of utterances to speak after the current one finishes.
+  std::queue<Utterance*> utterance_queue_;
+
+  // A set of delegates that want to be notified when the voices change.
+  std::set<VoicesChangedDelegate*> voices_changed_delegates_;
+
+  // A pointer to the platform implementation of text-to-speech, for
+  // dependency injection.
+  TtsPlatformImpl* platform_impl_;
+
+  // The delegate that processes TTS requests with user-installed extensions.
+  TtsEngineDelegate* tts_engine_delegate_;
+
+  DISALLOW_COPY_AND_ASSIGN(TtsControllerImpl);
+};
+
+#endif  // CHROME_BROWSER_SPEECH_TTS_CONTROLLER_IMPL_H_