Merge "HWUI: do not call glCopyTexSubImage2D on empty area." into nyc-dev am: e4e240f13f
am: e136aba4ad

* commit 'e136aba4adcef06eea4d237eb18b031704c37f59':
  HWUI: do not call glCopyTexSubImage2D on empty area.

Change-Id: I7a79fdcf6058dc8867c94ef2d66b6f7b5c3ab1ea