In case of removing summary element, we need to check details *frame* children
instead of details *element* children since the summary element has been
already removed from details element children list.
MozReview-Commit-ID: GEzDId9CYf9
Change the logic that moves the main summary to the front from operating
on generated frames in DetailsFrame::SetInitialChildList() to operating
on frame construction item list in AddFrameConstructionItemsInternal()
so that it will be correct when cooperating with ::first-line.
The root cause of the bug reported is because when specifying
::first-line on details element, the first frame of summary element,
which is generated due to ib-split, will be wrapped in nsFirstLineFrame.
The original code fails to find the summary frame in the wrapper frame
and triggers assertion because of the second ib-split summary frame. To
fix that, we need to descend into the child list of wrapper frames when
checking the main summary.
Add original test case as a crashtest as well as reftests to clearly
reproduce the issue.
Note that in the reftest, the blue color in ::first-line is applied
incorrectly to the second line in the summary due to bug 520605.
MozReview-Commit-ID: Bv4Vcvxp6pY
