Merge m-c to inbound. a=merge
Backed out changeset 65cda04dc8d2 (bug 1064432) for bustage on all platforms.
CLOSED TREE
Backed out changeset 96a507248c53 (bug 1059583) for Werror bustage.
CLOSED TREE
Bug 1055285 part 1: Implement CSS parsing & computation for 'object-fit' property. r=heycam
Bug 1055285 part 2: Implement CSS parsing & computation (but not animation) for 'object-position' property. r=heycam
Bug 1055285 part 3: Implement animation for 'object-position' property. r=heycam
Bug 1055285 part 4: Extend test_transitions_per_property.html with a few more scenarios for background-position & object-position transitions. (no review)
Bug 1050159. Apply correct dirty rect when AddCanvasBackgroundColorItem creates an nsDisplaySolidColor. r=mattwoodrow

--HG--
extra : rebase_source : a762a87108b7b7a36664a5590b43fbd28b4842d1
Bug 1062100. Part 1: Remove ItemCoversScrollableArea. r=mattwoodrow
This isn't really part of this bug but it simplifies related code.
Bug 1062100. Part 2: Assign clip rects to non-async-scrollable scrolled layers, and hide clipped layers if some non-moving layer covers their entire clip rect. r=mattwoodrow
Bug 1061045. Remove dirtyRect save/restore from Enter/LeavePresShell since they're not needed anymore. r=tn
Bug 1063052. NS_RUNTIMEABORT if a builtin stylesheet fails to load. r=heycam
Bug 1049195 - Call glFlush() for each frame if necessary r=jgilbert
Bug 1042426 - Adjust installer manifests for the new MOZ_SANDBOX flag. r=mshal

--HG--
extra : rebase_source : a71bedbd4bd8dcb72cdddb677e782e2f659fb35a
Bug 1061794 - move -Wshadow flags additions in layout/style/ to moz.build; r=mshal
Bug 1061791 - move CFLAGS usages in gfx/cairo/* to moz.build; r=mshal
Bug 1064587 - Cycle collect nsFormFillController. r=smaug
Bug 1028147 - Privatize public destructor of image::Decoder. r=seth
Bug 1058158 - run b2g marionette tests in test container, r=jgriffin
Bug 1008789: Init username to 0, just in case. r=drno