Bug 1078029 - Turn off touch event retargeting in fennec. r=wesj
Bug 1078029 - Add code to reposition input event coordinates into the target frame. r=roc

The PositionedEventTargeting code allows input events to be dispatched to a
target not directly under the input event point. However, the coordinates of the
input event can then end up outside the bounding rect of the event target. This
state is generally unexpected by web content and may cause compatibility issues.
Fennec's front-end code used to deal with this by repositioning the input event
coordinates to be inside the bounding rect; now that Fennec is using the shared
C++ code we need to have that code here. This behaviour is guarded by a pref and
disabled by default (but enabled on Fennec).
Bug 1078029 - Dispatch a dummy mouse event so that browser.js can pick up the event's retargeted target. r=wesj