Put the squashing layer underneath the ancestor clipping layer if present.

Previously, this was the case for m_graphicsLayer but not m_squashingLayer.
Since they now are guaranteed to have the same clipping ancestor, this is both
safe and correct.

BUG=336563

Review URL: https://codereview.chromium.org/215823002

git-svn-id: svn://svn.chromium.org/blink/trunk@170348 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove RenderTableRow::clippedOverflowRectForRepaint.

The table row clippedOverflowRectForRepaint override was being used to force
the row to have an overflow rect the same size as the parent tables overflow
rect. This causes overly large invalidations when, for example, the background
colour of a table row changes.

This CL removes RenderTableRow::clippedOverflowRectForRepaint() so we just
use the RenderBox method.

BUG=357291

Review URL: https://codereview.chromium.org/216883005

git-svn-id: svn://svn.chromium.org/blink/trunk@170349 bbb929c8-8fbe-4397-9dbb-9b2b20218538