For some kinds of changes we need to update the layer tree even though there is
no change to style. For example, if an animation is paused via the Web
Animations API, we need to remove the animation from the layer even though the
style will not change.
This patch detects such changes by making ElementRestyler check for an
out-of-date animation generation on layers. This is complicated by the fact that
we currently maintain *two* animation generation numbers: one for the set of
animations and one for the set of transitions, but we only have *one* animation
generation number on each layer. This is a known issue (bug 847286).
As a result, until bug 847286 is fixed, we need to be careful to compare against
the greater of the two numbers.
This is just moving one bit of data from the pres context without any
logic change. But given the other refactoring, it seems to make more
sense here now.
The MOZ_DEBUG_RESTYLE_STRUCTS environment variable can be set to a comma-
separated list of style struct names. When restyle logging is enabled,
this will cause the style context tree -- showing cached style struct
pointers for those structs specified -- to be logged before each
individual restyle is processed. It will also show the struct pointer
values involved when swapping structs between style contexts.
For example, set MOZ_DEBUG_RESTYLE_STRUCTS=Font,UserInterface to show
the cached nsStyleFont and nsStyleUserInterface pointers on the style
contexts involved in the restyle process.
Set the MOZ_DEBUG_RESTYLE environment variable and every restyle will have
detailed logging printed to stderr. By default, restyles for animations are
not logged; you can include them by also setting MOZ_DEBUG_RESTYLE_ANIMATIONS.
If you wish to limit restyle logging to a particular change, you can call
nsPresContext::StartRestyleLogging() and nsPresContext::StopRestyleLogging()
at appropriate points. (You might want to add a couple of helper methods
temporarily on nsIDocument and then expose them to your page with Web IDL
to make them easier to call.) You do not need to have set MOZ_DEBUG_RESTYLE
for this to work.
Set the MOZ_DEBUG_RESTYLE environment variable and every restyle will have
detailed logging printed to stderr. By default, restyles for animations are
not logged; you can include them by also setting MOZ_DEBUG_RESTYLE_ANIMATIONS.
If you wish to limit restyle logging to a particular change, you can call
nsPresContext::StartRestyleLogging() and nsPresContext::StopRestyleLogging()
at appropriate points. (You might want to add a couple of helper methods
temporarily on nsIDocument and then expose them to your page with Web IDL
to make them easier to call.) You do not need to have set MOZ_DEBUG_RESTYLE
for this to work.
Later patches will combine the coalescing of restyling between the
miniflush performed for animations and for transitions into a single
RestyleTracker, which will coalesce the work better. This patch changes
the API exposed for doing that so that the coalescing patch will contain
only the internals.
This depends on bug 898333 in order to avoid causing:
TEST-UNEXPECTED-FAIL | chrome://mochitests/content/chrome/dom/tests/mochitest/chrome/test_focused_link_scroll.xul | Assertion count 1 is greater than expected range 0-0 assertions.
due to the assertion:
###!!! ASSERTION: Shouldn't be trying to restyle non-elements directly: '!aContent || aContent->IsElement()', file ../../../layout/base/nsStyleChangeList.cpp, line 62
The assertion count change in layout/generic/crashtests/571995.xhtml is
expected because it changes us from having 7 of:
###!!! ASSERTION: Shouldn't be trying to restyle non-elements directly: '!aContent || aContent->IsElement()', file ../../../layout/base/nsStyleChangeList.cpp, line 62
with the stack:
mozilla::ElementRestyler::CaptureChange(nsStyleContext*, nsStyleContext*, nsChangeHint) [layout/base/nsChangeHint.h:191]
mozilla::ElementRestyler::RestyleSelf(nsRestyleHint) [layout/base/RestyleManager.cpp:2304]
to only having one. This is expected since this patch changes
RestyleSelf to only call CaptureChange for the first continuation or
block-in-inline sibling.
