Fix RenderBlock::nodeAtPoint() for scrollbars of hidden and pointer-events:none elements

Make sure that the RenderBlock is visible to the hit test request before
testing whether the test point is in an overflow control.

This is similar to the code a few lines down that performs hit testing
for the background.

BUG=313908

Review URL: https://codereview.chromium.org/68243009

git-svn-id: svn://svn.chromium.org/blink/trunk@164436 bbb929c8-8fbe-4397-9dbb-9b2b20218538
HTMLEntityTable could use char to reduce binary size

Merging from webkit CL http://trac.webkit.org/changeset/155559

Using LChar instead of UChar in HTMLEntityTable reduces the
binary size by around 18Kb.

Review URL: https://codereview.chromium.org/120393003

git-svn-id: svn://svn.chromium.org/blink/trunk@164437 bbb929c8-8fbe-4397-9dbb-9b2b20218538