Bug 848719 - No Tail delegation needed for Menu button. r=mfinkle, a=akeybl
Bug 848719 - TabsButton will have curve only one side. r=mfinkle, a=akeybl
Bug 851379 - Rollup of patches for Aurora. a=akeybl

Individual commit messages below.
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Bug 851379 part 1: Rename ComputeWidthDependentValue to ComputeCBDependentValue. r=mats
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Bug 851379 part 2: Make ComputeMargin, ComputePadding, and InitOffsets take a horizontal *and* vertical percent basis, so that we can resolve vertical margins and padding against containing block *height* in flex items. r=mats
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Bug 851379, part 3: Add reftest with percent-valued vertical margin & padding on flex items. r=mats
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Bug 851379, part 4: Fix InitOffsets logging code to display horizontal and vertical percent basis, instead of just a containing block width. r=mats
Bug 853364 - Backout bug 648730 to fix SIGBUS at startup (symbols clash) on OpenBSD after bug 648407. r=glandium, a=akeybl