[CSS Regions][Mac] fast/regions/full-screen-video-from-region.html hits an assertion...

[CSS Regions][Mac] fast/regions/full-screen-video-from-region.html hits an assertion in RenderFlowThread::removeRenderBoxRegionInfo
https://bugs.webkit.org/show_bug.cgi?id=106075

Patch by Andrei Bucur <abucur@adobe.com> on 2013-02-15
Reviewed by Tony Chang.

Source/WebCore:

The crash is caused by two issues.

The first problem is how a block inside a flow thread determines if the children needs relayout or not.
When the region chain is invalidated, the information is lost so we need to return true, even for the
enclosing RenderFlowThread. Because the video renderer is the first child of the flow thread this doesn't
happen.

The patch implements this behaviour by inspecting both if the region chain has changed and
if the block has no range computed yet.

The second problem is RenderMedia not inheriting from RenderBlock. The logic of child relayout doesn't apply
to it. In the test case, when the full screen button is pressed, the region changes width to fill the viewport,
the chain is invalidated and the box info hash map is cleared. When the video is laid out again (after fixing
the first issue) it has the same size so the controls don't do a layout. They remain without box info inside
the flow thread, thus causing the assertion.

The patch forces the controls to relayout if the region chain was invalidated. We can't use the
logicalWidthChangedInRegions method because it is block specific. This will be fixed in a later patch.

Tests: No new tests. fast/regions/full-screen-video-from-region.html no longer crashes.

* rendering/RenderBlock.cpp:
(WebCore::RenderBlock::checkForPaginationLogicalHeightChange):
* rendering/RenderFlowThread.cpp:
(WebCore::RenderFlowThread::RenderFlowThread):
(WebCore::RenderFlowThread::layout):
(WebCore::RenderFlowThread::logicalWidthChangedInRegions):
* rendering/RenderFlowThread.h: Renamed pageLogicalHeightChanged to pageLogicalSizeChanged.
* rendering/RenderMedia.cpp:
(WebCore::RenderMedia::layout):

LayoutTests:

Removed the crash/fail expectation for fast/regions/full-screen-video-from-region.html.

* platform/mac/TestExpectations:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@142982 268f45cc-cd09-0410-ab3c-d52691b4dbfc