Add checking queue size when calling handleSpeakingCompleted().

Source/modules/speech/SpeechSynthesis.cpp

Index: Source/modules/speech/SpeechSynthesis.cpp
diff --git a/Source/modules/speech/SpeechSynthesis.cpp b/Source/modules/speech/SpeechSynthesis.cpp
index 363ea98d9b61ad5827bb5219818c8e2ed56933a5..df9edebe210b78befa9b0afa520a79af676fe653 100644
--- a/Source/modules/speech/SpeechSynthesis.cpp
+++ b/Source/modules/speech/SpeechSynthesis.cpp
@@ -154,10 +154,12 @@ void SpeechSynthesis::handleSpeakingCompleted(SpeechSynthesisUtterance* utteranc
     ASSERT(utterance);
 
     bool didJustFinishCurrentUtterance = false;
+    int oldQueueSize = 0;

[haraken, 2014/08/21 01:01:22]

Can we introduce something like a |shouldStartSpeaking| flag and remove
|didJustFinishCurrentUtterance| and |oldQueueSize|?

bool shouldStartSpeaking = false;
if (utterance == currentSpeechUtterance()) {
  m_utteranceQueue.removeFirst();
  shouldStartSpeaking = !!m_utteranceQueue.size();
}

     // If the utterance that completed was the one we're currently speaking,
     // remove it from the queue and start speaking the next one.
     if (utterance == currentSpeechUtterance()) {
         m_utteranceQueue.removeFirst();
+        oldQueueSize = m_utteranceQueue.size();
         didJustFinishCurrentUtterance = true;
     }
 
@@ -168,7 +170,7 @@ void SpeechSynthesis::handleSpeakingCompleted(SpeechSynthesisUtterance* utteranc
     fireEvent(errorOccurred ? EventTypeNames::error : EventTypeNames::end, utterance, 0, String());
 
     // Start the next utterance if we just finished one and one was pending.
-    if (didJustFinishCurrentUtterance && !m_utteranceQueue.isEmpty() && !utterance->startTime())
+    if (didJustFinishCurrentUtterance && !m_utteranceQueue.isEmpty() && oldQueueSize)
         startSpeakingImmediately();
 }