Add logs for EME API calls.

BUG=224786
TEST=Use --webcore-log-channels=Media in command line to enable these logs.

Review URL: https://codereview.chromium.org/145213002

git-svn-id: svn://svn.chromium.org/blink/trunk@165674 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove CSS Variables from experimental features

CSS Variables currently have some performance issues to resolve.
This patch will disable CSS Variables during performance testing
while these issues are being worked on.

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/145993003

git-svn-id: svn://svn.chromium.org/blink/trunk@165675 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Cache SkTypeface in FontPlatformData on Mac

Before painting text on Mac, we call setupPaint, which would
use the CoreText font to create an SkTypeface object. Instead
of holding onto this, we were promptly throwing it away. Other
platforms keep the SkTypeface around on their version of
FontPlatformData. I'm mirroring that for Mac now.

The previous version of this patch caused assertions due to a
missing adoptRef :( You can find it at
https://codereview.chromium.org/141413002/

Review URL: https://codereview.chromium.org/138903018

git-svn-id: svn://svn.chromium.org/blink/trunk@165676 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Improve core/testing/InternalSettings exception messages.

BUG=270033

Review URL: https://codereview.chromium.org/143413007

git-svn-id: svn://svn.chromium.org/blink/trunk@165677 bbb929c8-8fbe-4397-9dbb-9b2b20218538