DevTools: replace timeline GPUEvent 'ownerPID' with 'foreign'

The ownerPID property is too generic and there's no need exposing it
to the user. It has been replaced with the 'foreign' boolean
that shows if a gpu task is caused by the inspected renderer or not.

BUG=298951
R=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/77433002

git-svn-id: svn://svn.chromium.org/blink/trunk@162375 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix comparison between signed and unsigned integer in WidthCache

Review URL: https://codereview.chromium.org/78503002

git-svn-id: svn://svn.chromium.org/blink/trunk@162376 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Improve XPathEvaluator exception messages.

BUG=270033

Review URL: https://codereview.chromium.org/78163002

git-svn-id: svn://svn.chromium.org/blink/trunk@162377 bbb929c8-8fbe-4397-9dbb-9b2b20218538