Unbreak libgui

Change I2c0f05d1f70b96ad801971f23f6f9cf4e0fa7167 broke libgui for a
bunch of pre-4.1 blobs by changing the surfaceclient API, so bring
it back

Change-Id: I1f6ce3b886539d0e972bbe41116192bf162be968
make TARGET_QCOM_DISPLAY_VARIANT more parametric

Change-Id: I36bba3ba96e174b443d800fd79957a1f428899df
Reset the FrameNumber for dropped frame in async mode

In Async, reset the framenumber of frames dropped by the BufferQueue.
This allows the client to dequeue and use this frame before the other
queued frames which may be with the MDP.

CRs-fixed: 448606

Change-Id: Icaabf77b55a7275dc98ba1fdfba89508feb92145
Check fence is not NULL before dereferencing it

If the fence obtained in dequeueBuffer is NULL, don't dereference it.
This will avoid a crash in surfaceflinger.

CRs-fixed: 516300
Change-Id: I3054dc37087103f3addae7884bb03460484a1eec
Surface: Initialize variable and add a defensive check.

Initialize buf variable and make sure to check for return
value of dequeueBuffer() before sending to the client.

Change-Id: I0569f2d45825fab0e5d0f38fc91a07990f57c7ab
Merge "Check fence is not NULL before dereferencing it" into cm-10.2
Merge "Surface: Initialize variable and add a defensive check." into cm-10.2