Attempt to deflake fast/css/font-weight-1.html

Attempt to deflake fast/css/font-weight-1.html

Update the fast/css/font-weight-1.html test to wait for the fonts loaded
promise to resolve thereby blocking on all webfonts to load. This should
ensure that the Windows try bots gets the correct expected image result.

BUG=521124
TBR=szager@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=201938

[eae, 2015-09-08 20:55:16]

eae@chromium.org changed reviewers:
+ szager@chromium.org

[eae, 2015-09-08 21:21:13]

Patchset #1 (id:1) has been deleted

[eae, 2015-09-08 23:04:06]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2015-09-08 23:04:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1334473002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1334473002/20001

[commit-bot: I haz the power, 2015-09-08 23:34:10]

Committed patchset #1 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=201938