Show warning message when webfont CORS-enabled fetching failed

This warning message should be tentative. We'll remove the warning once
we decide to restrict cross-origin webfont request (or not).

BUG=286681

Review URL: https://codereview.chromium.org/239923003

git-svn-id: svn://svn.chromium.org/blink/trunk@171822 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix SVG animations in shadow trees

This is a followup to [1] to fix SVG SMIL animations in shadow trees.
The main idea in this patch is to switch document() to treeScope() in
the id lookup.

This patch also contains two fixes for the remaining
targetElementFromIRIString instances that referenced document.

[1] https://src.chromium.org/viewvc/blink?view=rev&revision=171797

BUG=363927

Review URL: https://codereview.chromium.org/239263012

git-svn-id: svn://svn.chromium.org/blink/trunk@171823 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Retrying webfont fetching should continue only when fetchFont() succeeds

ResourceFetcher::fetchFont() may fail. If it fails, we should finish
fetching webfont immediately.

BUG=363517

Review URL: https://codereview.chromium.org/238683005

git-svn-id: svn://svn.chromium.org/blink/trunk@171824 bbb929c8-8fbe-4397-9dbb-9b2b20218538