AudioTrack: support ENCODING_IEC61937

Set DIRECT flag.
Use audio_has_proportional_frames() instead of audio_is_linear_pcm()
where appropriate.

Bug: 24541671
Bug: 20891646
Bug: 26373761
Change-Id: Ia32036b18683b084d6c9887593df87397ea0afd9
Signed-off-by: Phil Burk <philburk@google.com>
diff --git a/services/audioflinger/AudioStreamOut.h b/services/audioflinger/AudioStreamOut.h
index 06a2277..768f537 100644
--- a/services/audioflinger/AudioStreamOut.h
+++ b/services/audioflinger/AudioStreamOut.h
@@ -106,7 +106,7 @@
     uint64_t             mFramesWrittenAtStandby;
     uint64_t             mRenderPosition; // reset by flush or standby
     int                  mRateMultiplier;
-    bool                 mHalFormatIsLinearPcm;
+    bool                 mHalFormatHasProportionalFrames;
     size_t               mHalFrameSize;
 };