Bug 827844 - Fix flickering when layout changes on Firefox/android. r=kats,bgirard

Fix flickering that can occur when the surface size changes due to a layout
change (such as the virtual keyboard appearing/disappearing) on Android.
Bug 828249 - Fix fixed layer positioning when zoomed out beyond page bounds. r=kats

width/height parameters in CompositorParent got mixed up at some point.
Bug 828345 - Maintain aspect ratio for clamping scrollport. r=kats

Make sure the clamping scroll-port maintains its aspect ratio on Android. This
fixes fixed position elements appearing to jitter after zooming out beyond the
page boundaries.
Bug 828969 - Dispatch the mozbrowserasyncscroll event asynchronously, thus preventing deadlocks (and probably other problems). r=bz
Bug 815418: Telemetry for failed profile lock attempts; r=vladan

--HG--
extra : rebase_source : a7f1217bce0aa61c3c86eaa998e051d678ec7e1e
Bug 828607 - Fix exact rooting in jsproxy; r=evilpie
Bug 827749 - Aggressively duplicate file handles. r=cjones.
Bug 828870 - All shared blobs must be immutable. r=khuey.
Bug 818336 - Don't switch tabs when returning to a webapp. r=mfinkle
Bug 828120 - Social panel buttons are too wide on Mac. r=mattn