FastMixer update

Updates:
 - Add support for mono fast tracks
 - Add support for optional sample rate conversion on fast tracks
 - Log sample rate and frame count
 - Enable statistics

Change-Id: Ife014edf4f452da361f3eaaae19209ef6ff6958b
diff --git a/services/audioflinger/FastMixerState.cpp b/services/audioflinger/FastMixerState.cpp
index 4eacacf..139a1c8 100644
--- a/services/audioflinger/FastMixerState.cpp
+++ b/services/audioflinger/FastMixerState.cpp
@@ -19,7 +19,8 @@
 namespace android {
 
 FastTrack::FastTrack() :
-    mBufferProvider(NULL), mVolumeProvider(NULL), mGeneration(0)
+    mBufferProvider(NULL), mVolumeProvider(NULL), mSampleRate(0),
+    mChannelMask(AUDIO_CHANNEL_OUT_STEREO), mGeneration(0)
 {
 }