The problematic scenario is when the page is exactly the height of the screen
(with dynamic toolbar not visible). In this case, the scrollable() function in
Axis.java returns false on the vertical axis, and so the JavaPanZoomController
never does any scrolling. This in turns means that the scrollBy code in
LayerMarginsAnimator never gets to run, so you can never drag the toolbar back
into being visible. The patch ensures that scrollable() returns true when some
or all of the margins are not visible, ensuring that in these scenarios the
user can still scroll the toolbar back onto the screen. This patch also adds
some comments/asserts to verify the new code is threadsafe.
This adds a notification callback to PanZoomTarget that the PanZoomController
can call to notify GeckoLayerClient that a subdocument is being scrolled. This
allows GeckoLayerClient to call LayerMarginsAnimator and alter the margins
accordingly, stopping a page from trapping the toolbar on/off the screen with
a screen-covering subframe.
Refactor the dynamic toolbar code so that the ownership of various properties
is clearer, and the page is offset by the toolbar instead of being overlapped.
This fixes problems with the scroll origin of the page not corresponding to
the visible origin on the screen.
Refactor the dynamic toolbar code so that the ownership of various properties
is clearer, and the page is offset by the toolbar instead of being overlapped.
This fixes problems with the scroll origin of the page not corresponding to
the visible origin on the screen.
