Use containerless scrolling for root scroll frames. (bug 1076192, r=tnikkel)
Apply the correct clip rect when using containerless scrolling. (bug 1100756, r=tn)
Add a helper for tracking APZ input targets. (bug 1109985 part 1, r=dvander)
Handle APZ-aware scroll events on the widget, not ESM. (bug 1109985 part 2, r=kats)
Add a mapping from layer id to TabParent. (bug 1111873 part 1, r=dvander)
Correctly handle in-process wheel events on Windows APZ. (bug 1111873 part 2, r=kats)