Extend PlatformSpeechSynthesizerMock with an utterance queue.

Source/modules/speech/SpeechRecognitionEvent.h

Index: Source/modules/speech/SpeechRecognitionEvent.h
diff --git a/Source/modules/speech/SpeechRecognitionEvent.h b/Source/modules/speech/SpeechRecognitionEvent.h
index 20a9008bdf66dc56cd08cbde80bbe01cbd71fa09..ed5018fccf24c4d9b6337d86cf3011d5e208ef38 100644
--- a/Source/modules/speech/SpeechRecognitionEvent.h
+++ b/Source/modules/speech/SpeechRecognitionEvent.h
@@ -47,11 +47,11 @@ public:
     static PassRefPtrWillBeRawPtr<SpeechRecognitionEvent> createNoMatch(SpeechRecognitionResult*);
 
     unsigned long resultIndex() const { return m_resultIndex; }
-    SpeechRecognitionResultList* results() const { return m_results.get(); }
+    SpeechRecognitionResultList* results() const { return m_results; }
 
-    // These two methods are here to satisfy the specification which requires these attrubutes to exist.
-    Document* interpretation() { return 0; }
-    Document* emma() { return 0; }
+    // These two methods are here to satisfy the specification which requires these attributes to exist.
+    Document* interpretation() { return nullptr; }
+    Document* emma() { return nullptr; }
 
     // Event
     virtual const AtomicString& interfaceName() const override;