Only send TTS VoicesChanged callbacks when TTS has been explicitly requested.

chrome/browser/speech/tts_controller_impl.cc

Index: chrome/browser/speech/tts_controller_impl.cc
diff --git a/chrome/browser/speech/tts_controller_impl.cc b/chrome/browser/speech/tts_controller_impl.cc
index 2e8a83510347f3f27bf8ca1ed9646a794882a1c1..9cd26afe6e43ff3230f026948d90f5a573391c88 100644
--- a/chrome/browser/speech/tts_controller_impl.cc
+++ b/chrome/browser/speech/tts_controller_impl.cc
@@ -437,6 +437,11 @@ int TtsControllerImpl::GetMatchingVoice(
 }
 
 void TtsControllerImpl::VoicesChanged() {
+  // Existence of platform tts indicates explicit requests to tts. Since
+  // |VoicesChanged| can occur implicitly, only send if needed.
+  if (!platform_impl_)
+    return;
+
   for (std::set<VoicesChangedDelegate*>::iterator iter =
            voices_changed_delegates_.begin();
        iter != voices_changed_delegates_.end(); ++iter) {