Bug 1023928 - [System][UX] The waiting icon now comes with a dirty dot. r=nical, a=2.0+
Bug 1034240 - Trigger an update of the displayport margins on a new APZC if the content already has margins. r=botond, a=2.0+
Bug 1023473 - Pad out tile contents by one pixel. r=BenWa, a=2.0+

This fixes reading unitialized data during texture filtering.
It's complicated because we can have regions of initialized data
and padding out a region is much harder than a rectangle.

We currently only take this path for tiled things because of
the artifacts that show up during the sampling that helps
in overscroll. It's also not a great long term solution because
it only works for software backends.