Clean up frame size in AudioTrack and AudioFlinger

TrackBase::mFrameSize, mChannelMask, and mChannelCount are now const.
Use TrackBase::mFrameSize instead of re-calculating frame size.
AudioFlinger only sees 16-bit PCM format, conversion from 8-bit is
  now entirely on the client side.  Previously a small part of the
  responsibility was on server side also.
size_t is unsigned, so use %u in logs.
Fix theoretical bug where TrackBase constructor was over-allocating space
  for non-linear AudioTrack or 8-bit PCM AudioRecord (probably benign).

Change-Id: I7cbbba0bf4dba29ea751d8af341ab8e5cbbdc206
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index 8816929..9ddfe28 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -473,14 +473,13 @@
             const uint32_t      mSampleRate;    // initial sample rate only; for tracks which
                                 // support dynamic rates, the current value is in control block
             const audio_format_t mFormat;
-            size_t              mFrameSize; // AudioFlinger's view of frame size in shared memory,
+            const audio_channel_mask_t mChannelMask;
+            const uint8_t       mChannelCount;
+            const size_t        mFrameSize; // AudioFlinger's view of frame size in shared memory,
                                             // where for AudioTrack (but not AudioRecord),
                                             // 8-bit PCM samples are stored as 16-bit
-                                            // FIXME should be const
             bool                mStepServerFailed;
             const int           mSessionId;
-            uint8_t             mChannelCount;
-            audio_channel_mask_t mChannelMask;
             Vector < sp<SyncEvent> >mSyncEvents;
         };