Implement web speech synthesis.

chrome/renderer/tts_dispatcher.h

Index: chrome/renderer/tts_dispatcher.h
diff --git a/chrome/renderer/tts_dispatcher.h b/chrome/renderer/tts_dispatcher.h
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+// Copyright (c) 2013 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_RENDERER_TTS_DISPATCHER_H_
+#define CHROME_RENDERER_TTS_DISPATCHER_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/hash_tables.h"
+#include "content/public/renderer/render_view.h"
+#include "ipc/ipc_channel_proxy.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebSpeechSynthesizer.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebSpeechSynthesizerClient.h"
+
+class RenderViewImpl;
+struct TtsVoice;
+
+// TtsDispatcher is a delegate for methods used by WebKit for
+// speech synthesis APIs. It's the complement of
+// TtsDispatcherHost (owned by RenderViewHost).
+class TtsDispatcher
+    : public WebKit::WebSpeechSynthesizer,
+      public IPC::ChannelProxy::MessageFilter {
+ public:
+  explicit TtsDispatcher(WebKit::WebSpeechSynthesizerClient* client);
+
+ private:
+  virtual ~TtsDispatcher();
+
+  // IPC::ChannelProxy::MessageFilter override.
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  // WebKit::WebSpeechSynthesizer implementation.
+  virtual void updateVoiceList() OVERRIDE;
+  virtual void speak(const WebKit::WebSpeechSynthesisUtterance& utterance)
+      OVERRIDE;
+  virtual void pause() OVERRIDE;
+  virtual void resume() OVERRIDE;
+  virtual void cancel() OVERRIDE;
+
+  WebKit::WebSpeechSynthesisUtterance FindUtterance(int utterance_id);
+
+  void OnSetVoiceList(const std::vector<TtsVoice>& voices);
+  void OnDidStartSpeaking(int utterance_id);
+  void OnDidFinishSpeaking(int utterance_id);
+  void OnDidPauseSpeaking(int utterance_id);
+  void OnDidResumeSpeaking(int utterance_id);
+  void OnWordBoundary(int utterance_id, int char_index);
+  void OnSentenceBoundary(int utterance_id, int char_index);
+  void OnMarkerEvent(int utterance_id, int char_index);
+  void OnWasInterrupted(int utterance_id);
+  void OnWasCancelled(int utterance_id);
+  void OnSpeakingErrorOccurred(int utterance_id,
+                               const std::string& error_message);
+
+  // The WebKit client class that we use to send events back to the JS world.
+  // Weak reference, this will be valid as long as this object exists.
+  WebKit::WebSpeechSynthesizerClient* synthesizer_client_;
+
+  // Message loop for the main render thread. Utilized to
+  // ensure that callbacks into WebKit happen on the main thread
+  // instead of the originating IO thread.
+  scoped_refptr<base::MessageLoopProxy> main_loop_;
+
+  // Next utterance id, used to map response IPCs to utterance objects.
+  static int next_utterance_id_;
+
+  // Map from id to utterance objects.
+  base::hash_map<int, WebKit::WebSpeechSynthesisUtterance> utterance_id_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(TtsDispatcher);
+};
+
+#endif  // CHROME_RENDERER_TTS_DISPATCHER_H_