Use new skia drawDRRect API for roundrect borders

Although the DRRect API isn't yet fully optimized, this should be no slower
than before, and providing skia with the higher level information that the
path is a roundrect (as opposed to a generic spline) should give skia a much
better chance to optimize common cases such as a one-pixel wide border.

Brian assures me that on the GPU this will be much faster, on the CPU
it should currently remain the same. I haven't run a full performance
study yet.

Patch by Greg Humphreys ("I" in the comments above).

BUG=343347
R=esprehn@chromium.org, reed@google.com

Review URL: https://codereview.chromium.org/180173005

git-svn-id: svn://svn.chromium.org/blink/trunk@168050 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add a common autosizing test helper script

All autosizer tests have a common setup routine involving enabling
autosizing and printing a special message about how to run the tests
manually. This patch introduces a common script (autosizingTest.js) for
this functionality. In addition to cleaning up copy pasta code, this
will let us change the setup/error message easily in the future.

virtual/fasttextautosizing tests will be updated in a followup.

resources/autosizingTest.js (hidden in the middle of the files) is the
primary change in this patch.

This patch was mostly autogenerated with:
find . -type f -print0 | xargs -0 perl -0777 -i -pe 'BEGIN{undef $/;} s/<script.*\/script>/<script src="resources\/autosizingTest.js"><\/script>/smg'

BUG=

Review URL: https://codereview.chromium.org/180723009

git-svn-id: svn://svn.chromium.org/blink/trunk@168051 bbb929c8-8fbe-4397-9dbb-9b2b20218538