Bug 853946: Replace flex container's cached content-box cross-size and cached ascent with local variables in Reflow(). rs=Waldo
Bug 785468: Compute flex container's baseline as-described in the spec. r=dbaron
Bug 841876: Enable flexbox pref in release builds. r=dbaron
Bug 856199: Remove nsHTMLReflowState's no-longer-needed AutoRestore #include. r=dbaron