Fix bug 2045197.
The TTS settings activity uses the default TTS stream type. Associate
the volume control of this stream type with the volume control buttons.
diff --git a/src/com/android/settings/TextToSpeechSettings.java b/src/com/android/settings/TextToSpeechSettings.java
index e17a6d6..d3d59fa 100644
--- a/src/com/android/settings/TextToSpeechSettings.java
+++ b/src/com/android/settings/TextToSpeechSettings.java
@@ -92,6 +92,8 @@
 
         addPreferencesFromResource(R.xml.tts_settings);
 
+        setVolumeControlStream(TextToSpeech.Engine.DEFAULT_STREAM);
+
         mEnableDemo = false;
         initClickers();
         initDefaultSettings();