https://bugs.webkit.org/show_bug.cgi?id=62746
Crash possible when switching scrollbar appearance preference on Mac
-and corresponding-
<rdar://problem/9323983>
Reviewed by Simon Fraser.
This crash happens because the current mechanism that is intended to flag
ScrollAnimators as being in the page cache or not does not work correctly.
Long-term the fix for this is to move the ScrollableArea HashSet to a more
appropriate place. In the meantime, this patch addresses the crash by getting
rid of the m_isActive bool on ScrollAnimator that was intended to represent
whether or not the ScrollableArea is in the page cache. Instead, ScrollableArea
implementations now have their own functions to compute whether they are in
active pages. ScrollAnimator::setIsActive() needs to be kept around even though
there is no bool to flip anymore because scrollbars may need to be properly
updated if the appearance was switched while the document was in the page cache.
No longer call FrameView::setAnimatorsAreActive() from
Document::setIsInPageCache(), instead call it in
Document::documentDidBecomeActive()
* dom/Document.cpp:
(WebCore::Document::setInPageCache):
(WebCore::Document::documentDidBecomeActive):
ScrollableAreas can now assess whether or not they are on active pages (ie, not
in the page cache).
* platform/ScrollableArea.h:
(WebCore::ScrollableArea::isOnActivePage):
* rendering/RenderLayer.cpp:
(WebCore::RenderLayer::isOnActivePage):
* rendering/RenderLayer.h:
* rendering/RenderListBox.cpp:
(WebCore::RenderListBox::isOnActivePage):
* rendering/RenderListBox.h:
A FrameView cannot access its Document when it's in the page cache, so it
usually determines whether it's in the page cache by checking if its frame
points to a FrameView other than itself.
* page/FrameView.cpp:
(WebCore::FrameView::isOnActivePage):
Make sure ScrollableAreas are on active pages before setting them as
active. This will not be necessary when the HashSet become a per-web page
HashSet.
(WebCore::FrameView::setAnimatorsAreActive):
* page/FrameView.h:
ScrollAnimator no longer tracks the m_isActive bool.
* platform/ScrollAnimator.cpp:
(WebCore::ScrollAnimator::ScrollAnimator):
* platform/ScrollAnimator.h:
(WebCore::ScrollAnimator::setIsActive):
setIsActive() now exclusively calls updateScrollStyle() if there is a pending
need to do so.
* platform/mac/ScrollAnimatorMac.h:
* platform/mac/ScrollAnimatorMac.mm:
(WebCore::ScrollAnimatorMac::setIsActive):
Return early if the ScrollableArea is in the page cache.
(WebCore::ScrollAnimatorMac::updateScrollerStyle):
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@88982 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/WebCore/platform/ScrollableArea.h b/Source/WebCore/platform/ScrollableArea.h
index e919cee..36131fd 100644
--- a/Source/WebCore/platform/ScrollableArea.h
+++ b/Source/WebCore/platform/ScrollableArea.h
@@ -136,6 +136,8 @@
virtual bool shouldSuspendScrollAnimations() const { return true; }
virtual void scrollbarStyleChanged() { }
virtual void setVisibleScrollerThumbRect(const IntRect&) { }
+
+ virtual bool isOnActivePage() const { ASSERT_NOT_REACHED(); return true; }
bool isHorizontalScrollerPinnedToMinimumPosition() const { return !horizontalScrollbar() || scrollPosition(horizontalScrollbar()) <= minimumScrollPosition().x(); }
bool isHorizontalScrollerPinnedToMaximumPosition() const { return !horizontalScrollbar() || scrollPosition(horizontalScrollbar()) >= maximumScrollPosition().x(); }
