- Added specialized rect clipping functionality to Matrix4x4::ProjectRectBounds
so we don't have to return infinite values when rects cross the w=0 plane
in homogenous coordinate space.
- Updated callsites of ProjectRectBounds to pass a clipping rect that is
appropriate for the units that are returned.
This adds support for class="reftest-opaque-layer" and for
reftest-assigned-layer="some-layer-name" to the reftest harness.
From reftest/README.txt:
Opaque Layer Tests: class="reftest-opaque-layer"
================================================
If an element should be assigned to a PaintedLayer that's opaque, set the class
"reftest-opaque-layer" on it. This checks whether the layer is opaque during
the last paint of the test, and it works whether your test is an invalidation
test or not. In order to pass the test, the element has to have a primary
frame, and that frame's display items must all be assigned to a single painted
layer and no other layers, so it can't be used on elements that create stacking
contexts (active or inactive).
Layerization Tests: reftest-assigned-layer="layer-name"
=======================================================
If two elements should be assigned to the same PaintedLayer, choose any string
value as the layer name and set the attribute reftest-assigned-layer="yourname"
on both elements. Reftest will check whether all elements with the same
reftest-assigned-layer value share the same layer. It will also test whether
elements with different reftest-assigned-layer values are assigned to different
layers.
The same restrictions as with class="reftest-opaque-layer" apply: All elements
must have a primary frame, and that frame's display items must all be assigned
to the same PaintedLayer and no other layers. If these requirements are not
met, the test will fail.
Once we're smarter about recycling the right layer, we can't decide on a layer
as soon as we encounter its first display item. We might need to have to look
at all of the assigned display items. This change makes that requirement
explicit.
The calls above don't need access to the PaintedLayer, but the ones this change
is moving down do. This change just makes it more obvious that we're free to
move the calls to an even later point.
UpdateCommonClipCount accesses the PaintedLayerData's mLayer field in order to
get the layer manager. We want to be able to call UpdateCommonClipCount when
mLayer is null.
When choosing a painted layer for the event region item we must report the bounds of the hit regions as the bounds so that we don't fall through to the bottom most painted layer.
Sometimes, in very specific cases, the visible region gets simplified to one rect and is thus much bigger than the draw region. This becomes a problem if we decide to pull an opaque background color from a lower layer so that we are opaque. In which case we draw the background color over the whole visible region. But we use the draw region to determine if we can place items below this layer, so that background color could cover them incorrectly.
