Revert "Revert "Allow clipping by scroll parents." and "Improve perf of CalculateDrawPropertiesInternal when there are no scroll parents.""

This reverts commit 97ada322de9f492e3f0d1741ac117fc42599451b.

This was a speculative perf revert; seems not to be the issue. Relanding.

Local tests with and without this patch on a Nexus 4 with and without my patch didn't show a perf regression (in fact, perf seemed to mysteriously improve -- I assume this is noise).

TBR=danakj@chromium.org
BUG=306926

Review URL: https://codereview.chromium.org/26135005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229221 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229221