fix copy back dirty region

Copyback dirty region logic does copyback,
even when its not necessary causing 2ms delay.
Fix the logic to copy back only what is necessary.

Change-Id: I52de68258ac9f87d704ee5401f93417805fa6773
surfaceflinger: Set max acquired buffer count

If triple framebuffers are enabled, the number of acquired
buffers isn't increased by default. Set the count to one less
than the max buffers to make sure all three buffers come into
play.

Change-Id: I65054ed4004607f5be68c893f6f621e821cfbf1c
Merge "fix copy back dirty region"
Merge "surfaceflinger: Set max acquired buffer count"
libs/ui: Fix crash issue because of null pointer access

- handle NULL check is required while flatten GraphicsBuffer

CRs-fixed: 579102

Change-Id: I292b4b25dc1f5320378cc9e4affbad326e1fdaed
Merge "libs/ui: Fix crash issue because of null pointer access"
Hacks to support Sony MR0 camera blobs