Bug 1090398 - Update the APZ docs to reflect the new hit-testing design. r=botond
Bug 1090398 - Use EventRegions objects instead of nsIntRegions for tracking APZ hit-test areas. r=botond

This simply swaps out the existing nsIntRegion used in APZ hit-testing for
an EventRegion object. The dispatch-to-content region inside the EventRegions
is kept empty, and there are no functional changes here.
Bug 1090398 - Add support for using the layer event regions for hit testing. r=botond

When the event-regions are provided by layout, use them to populate the APZ-side
hit testing regions. The existing code is still used when event-regions are not
provided by layout.
Bug 1090398 - Small refactoring that adds ParentLayerPixel::ToUntyped. r=botond
Bug 1090398 - Workaround for scrollinfo layers not yet having event regions set up correctly. r=botond

Until bug 1082594 is fixed, the area occupied by inactive scrollable subframes
don't get added to their layer's dispatch-to-content region. Therefore the APZ
code doesn't know what area corresponds to the subframe, even though it knows
there is a subframe because of the scrollinfo layer. This change inserts a small
workaround to deal with the scrollinfo layers specially, so that the composition
bounds from the scrollinfo layer is used to obtain the area. Once bug 1082594
is fixed this can probably be removed.
Bug 1090398 - Distinguish the various outcomes of APZ hit testing more explicitly. r=botond

Previously we output of APZ hit testing was an APZC instance and an "in
overscroll" flag. Now we need to also distinguish between the hit region and the
dispatch-to-content region for an APZC, so this patch introduces an enum that
makes this more explicit.
Bug 1090398 - Require APZC target confirmation before input blocks are ready for handling. r=botond

For proper hit-testing we need to deal with situations where the initial touch
input falls on a dispatch-to-content region of an APZC, and the main thread
later tells us that it actually hit another APZC. This patch allows input blocks
to have an "unconfirmed" APZC target for the initially-found target that can
then be replaced with a different target. Input blocks without a confirmed
target are not ready for processing.
Bug 1090398 - Add basic gtests for the event-regions based hit-testing code. r=botond