Make more sense of Element::recalcStyle with ASSERTs

Move the clearNeedsStyleRecalc() and clearChildNeedsStyleRecalc() calls in
recalcStyle to allow ASSERTing that the parent style is always up to date and
that we only enter the related functions at the right time.

This exposed a bug in PseudoElement where it claimed it was inDocument 
immediately even before insertedInto() which meant the addToTopLayer call in
createPseudoElement was leaving childNeedsStyleRecalc bits in the tree after
running recalcStyle. The inDocument trick is no longer needed after r161195
where I made PseudoElement go through the normal Element lifecycle.

Review URL: https://codereview.chromium.org/63733002

git-svn-id: svn://svn.chromium.org/blink/trunk@161568 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Collapse WebIDBCallbacks and WebIDBCallbacksImpl

R=jamesr@chromium.org,alecflett@chromium.org,dgrogan@chromium.org
BUG=234277

Review URL: https://codereview.chromium.org/51943006

git-svn-id: svn://svn.chromium.org/blink/trunk@161569 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove Scrollbar dependency on AXObjectCache

Move AXObjectCache usage from platform files to FrameView.

Based on https://bugs.webkit.org/show_bug.cgi?id=114514

BUG=

Review URL: https://codereview.chromium.org/65573002

git-svn-id: svn://svn.chromium.org/blink/trunk@161570 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Suppressions for more flaky layout tests.

BUG=316425,316429
TBR=antonm@chromium.org,yhirano@chromium.org

Review URL: https://codereview.chromium.org/62673003

git-svn-id: svn://svn.chromium.org/blink/trunk@161571 bbb929c8-8fbe-4397-9dbb-9b2b20218538