Backed out 2 changesets (bug 872701)
CLOSED TREE

Backed out changeset 8fcfc380bfc9 (bug 872701)
Backed out changeset 31014a7ee3ab (bug 872701)
Bug 925226 - Fix incorrect downcast in signaling unittest. r=abr
Bug 923309 - Don't flush CGContext drawing to the window when we're only meant to be completing any pending drawing. r=Bas
Bug 923290 -  Don't use the window CGContext as a source with Moz2D. r=Bas