Dynamic updating recent menu for tabs from other devices.

If user opens recent/history menu and at the same moment syncronization
is updating session from other devices then user will can see
non-relevant a list of opened tabs from the other devices.

It's easy to reproduce.
1. Open a browser with enabled syncronization.
2. Open chrome://sync-internals page.
3. Open recent/history menu and wait for updating session on
   chrome://sync-internals page.
4. Open new tab on other synced device.
5. When chrome://sync-internals shows that session was updated the
   opened menu will show previous state of list list of opened tabs
   from the other devices.

R=pkasting@chromium.org, pavely@chromium.org

Review-Url: https://codereview.chromium.org/2768633003
Cr-Commit-Position: refs/heads/master@{#460503}
9 files changed