Extend PlatformSpeechSynthesizerMock with an utterance queue.

Source/modules/speech/testing/PlatformSpeechSynthesizerMock.h

 /*
  * Copyright (C) 2013 Apple Computer, Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 18 matching lines @@
 #include "platform/Timer.h"
 #include "platform/heap/Handle.h"
 #include "platform/speech/PlatformSpeechSynthesizer.h"
 
 namespace blink {
 
 class PlatformSpeechSynthesizerMock final : public PlatformSpeechSynthesizer {
 public:
     static PlatformSpeechSynthesizerMock* create(PlatformSpeechSynthesizerClient*);
 
-    virtual ~PlatformSpeechSynthesizerMock();
-    virtual void speak(PlatformSpeechSynthesisUtterance*) override;
-    virtual void pause() override;
-    virtual void resume() override;
-    virtual void cancel() override;
+    ~PlatformSpeechSynthesizerMock() override;
+    void speak(PlatformSpeechSynthesisUtterance*) override;
+    void pause() override;
+    void resume() override;
+    void cancel() override;
 
-    virtual void trace(Visitor*) override;
+    void trace(Visitor*) override;
 
 private:
     explicit PlatformSpeechSynthesizerMock(PlatformSpeechSynthesizerClient*);
-    virtual void initializeVoiceList() override;
+
+    void initializeVoiceList() override;
+
+    void speakNext();
+    void speakNow();
+
+    void speakingErrorOccurred(Timer<PlatformSpeechSynthesizerMock>*);
     void speakingFinished(Timer<PlatformSpeechSynthesizerMock>*);
-    void speakingErrorOccurred(Timer<PlatformSpeechSynthesizerMock>*);
 
+    Timer<PlatformSpeechSynthesizerMock> m_speakingErrorOccurredTimer;
     Timer<PlatformSpeechSynthesizerMock> m_speakingFinishedTimer;
-    Timer<PlatformSpeechSynthesizerMock> m_speakingErrorOccurredTimer;
-    Member<PlatformSpeechSynthesisUtterance> m_utterance;
+
+    Member<PlatformSpeechSynthesisUtterance> m_currentUtterance;
+    HeapDeque<Member<PlatformSpeechSynthesisUtterance>> m_queuedUtterances;
 };
 
 } // namespace blink
 
 #endif // PlatformSpeechSynthesizer_h