stagefright: add ClockEstimator API and WindowedLinearFitEstimator

Change-Id: I74474c385848a8eab2ac0da7c069510378e2b217
Smooth out AwesomePlayer

Use clock estimator to smooth out audio time stamps.

Change-Id: Iec1ff30c011069d06ff8051fc4839d00895463d6
audioflinger: Stop resetting compress offload streams

 * This code should only be invoked for legacy DirectTrack.
 * Fixes issues with compress offload failing due to lack
   of metadata after skip / seek.

Change-Id: I4e2eef6421421532556ba411542cfe2f9c1e3802
audio:Avoid AudioTrackThread if Track creation fails

-mAudioTrackThread is starting before the track creation.
 This thread is used to process the audio buffer, which
 is no longer valid if the track creation itself is
 failing.

-Fix is to check for the result of track creation and
 based on the result need to start the mAudioTrackThread.

Change-Id: Ic69e45f4269408ff60fe83390e9f8d0c895582e3
CRs-Fixed: 611668
libstagefright: Fix incorrect comparison of mimetype

'sizeof' is used to calculate length of string constant which returns
size of pointer to string constant. This causes comparison of only
four characters of mimetype. By using strlen, entire mimetype string
is compared - which returns correct result.

Change-Id: I4d081d3452f167d49aebbe3219e8e522ec29d5be
CRs-Fixed: 664311
 libstagefright: Use channel count if channel mask is zero.

-If the channel mask which is part of the meta data is zero use
 a valid channel count to update the channel mask.
-PCM offload playback for wav clips fails for some clips because
 channel mask part of the wave header is zero.

CRs-Fixed: 664374
Change-Id: I1bd5f2cc56fbc1eb9a6e04d219185690d3ce409c
libstagefright: Fix app crash during pcm offload playback

 -ANR is seen with trick mode operations during
  pcm offload playback.
 -If Player issues the read request to omx client while omx client is
  in pausing state, it moves the client to executing state if variable
  mPasued is true and it never returns from pause.
 -Do not set the variable mPaused to true while it is in pausing state.

Change-Id: Ib824f3a651f738be26df8906d7175eb59ce82fab