This commit adds a buffer unrotate operation to DrawTarget. It's
initially implemented with LockBits in DrawTarget. DrawTargetDual
overrides the implementation to pass on the operation to it's
DrawTargets.
No override is given for DrawTargetCapture as we intentionally
avoid this code path when async painting as it can fail.
This is needed so that RotatedBuffer can expose a single DrawTarget,
which can be a DrawTarget (for normal alpha), DrawTargetDual (for
component alpha), or DrawTargetCapture (when async painting).
MozReview-Commit-ID: csjjZ733hl
--HG--
rename : gfx/layers/BufferUnrotate.cpp => gfx/2d/BufferUnrotate.cpp
rename : gfx/layers/BufferUnrotate.h => gfx/2d/BufferUnrotate.h
extra : rebase_source : 5d96e2a5d36a01f2f9992adb37830e56436c7c35
extra : source : 64cb50b227e0ae604653f03ce2e892493126392e
a71d0035ad