Conditional discard in loop test

Test for issue with conditional discard in loop for angle directx 11
implementation
Merge pull request #656 from TiborsHub/master

Conditional discard in loop test
Changed status of four extensions to Ratified following a Khronos vote.
Merge pull request #657 from toji/extension_ratify

Changed status of four extensions to Ratified following a Khronos vote.
Log document visibility at each requestAnimationFrame call.
Merge pull request #658 from zhenyao/log

Log document visibility at each requestAnimationFrame call.