Finish ChromeTabbedActivity if its tabs have been merged into another instance

If Chrome's process is restarted while two ChromeTabbedActivity instances are running
it is possible to end up in an odd state where tabs are merged into one instance
and the task for the second instance is still running. This second task doesn't
have an activity associated with it yet, so we cannot kill the task when we
merge into the first instance. To work around this, when the second instance is
resumed it is finished immediately if its tabs have been merged into another instance.

BUG=657418

Review-Url: https://codereview.chromium.org/2448433003
Cr-Commit-Position: refs/heads/master@{#427441}
1 file changed