Behavior (visual) changes should be very minor. Things that are to be expected:
* A few things were not color managed correctly by the transform canvas (color emoji, some color filters). Those will be handled correctly with the tagged surfaces (although we're always transforming to sRGB, so nothing should change until we target a wider gamut).
* Image filtering will happen in the source color space, rather than the destination. Very minor.
* The transform canvas did caching of images in the destination color space. Now, the conversion happens at draw time. If there are performance issues, images can be pre-converted to the destination with makeColorSpace().
Building image encoding into the engine bloated the
binary size. This change will return raw bytes, and
callers who use this functionality can take on the
dependency on image encoding in their apps (via a
Dart package or a platform plugin).
Fixes https://github.com/flutter/flutter/issues/16537