Bug 880137 part 7: Point flexbox-sizing-* to the layout algorithm chunk of the flexbox spec.
Bug 879149 - Don't attempt to use ContentClientIncremental when not using GL layers. r=nrc
Bug 852850 - Follow-up to improve failure output with reftest-no-paint. r=dbaron
Bug 877036 - Make SharedMemory's memory reporter threadsafe. r=jlebar