Bug 903327 - Use device pixels per css pixel when calculating default font sizes. r=kats
Backed out 7 changesets (bug 906088) for robocop failures on a CLOSED TREE.

Backed out changeset c5b4781bd918 (bug 906088)
Backed out changeset a498d1641c16 (bug 906088)
Backed out changeset fcff9ef5cf7d (bug 906088)
Backed out changeset cf1603d47f6c (bug 906088)
Backed out changeset 8671264a5aaa (bug 906088)
Backed out changeset 01d6b977021f (bug 906088)
Backed out changeset 2910cc092c19 (bug 906088)
Backout changeset 2766d0ee65c5 (bug 903802) to fix bug 906378.
Bug 914937: Remove nsFlexContainerFrame::GetSkipSides, now that we can inherit a useful impl from nsSplittableFrame. r=mats
Bug 915344: Make variables 'SAMPLES' and 'numSamplesReadFromInput' unsigned, to fix build warning in mediaconduit_unittests.cpp. r=jesup