virtual/gpu/fast/hidpi/image-set-as-background.html flaky image failure on win7
virtual/gpu/fast/hidpi/image-set-as-background.html flaky image failure on win7

TBR=vollick@chromium.org
NOTRY=true
BUG=245611

Review URL: https://codereview.chromium.org/15745026

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@151536 bbb929c8-8fbe-4397-9dbb-9b2b20218538

primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs