DevTools: Do not blink the toolbar chevron icon on startup
DevTools: Do not blink the toolbar chevron icon on startup

The chevron icon blinks on the toolbar when DevTools are starting
on a slow machine.

R=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/14122020

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@148668 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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