Bug 956108 - [Holly] Part 1: Backout 9e7f91032d7d (which backed out d0255c4b2adc). r=bustage-fix.
Bug 956108 - [Holly] Part 2: Sync up Holly's nsRegion implementation with mozilla-central's. r=bustage-fix.
Bug 956108 - [Holly] Part 3: Disable test_leaf_layers_partition_browser_window.xul for d2d enabled Windows. r=roc.