Reland "Modify supercluster multiplier logic".

This relands http://crrev.com/231663006, which was reverted in http://crrev.com/235993003 due to http://crbug.com/362975.

The logic in maxClusterWidthProvider has been updated to avoid returning null.

BUG=361749
R=pdr@chromium.org

Review URL: https://codereview.chromium.org/237063007

git-svn-id: svn://svn.chromium.org/blink/trunk@171517 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix positioning of link highlights for squashed layers.

Previously, these had been positioned wrt the grouped mapping for the
squashed layer. This was wrong. The squashing layer (m_squashingLayer)
is often offset from the CLM. The result is that the link highlight
does not accout for the position of the m_squashingLayer and it's not
aligned with the stuff it's supposed to highlight.

R=abarth@chromium.org
BUG=351056

Review URL: https://codereview.chromium.org/237763003

git-svn-id: svn://svn.chromium.org/blink/trunk@171518 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Mark tests as failing for upcoming change.

https://codereview.chromium.org/220103002/ will cause these tests to
fail.  They'll need to be updated after that patch has rolled into
blink.

BUG=356805
TEST=LayoutTests.
NOTRY=true

Review URL: https://codereview.chromium.org/238473002

git-svn-id: svn://svn.chromium.org/blink/trunk@171519 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove unused parts of WebInputEventFactoryWin.

Almost everything seems to go through the Aura path now.

BUG=363455

Review URL: https://codereview.chromium.org/235883008

git-svn-id: svn://svn.chromium.org/blink/trunk@171521 bbb929c8-8fbe-4397-9dbb-9b2b20218538