Force-setting default browser through policy should not crash.

Force-setting default browser through policy should not crash.

The call to set chrome as default browser due to policy needs to happen on the FILE
thread. This change affects the call to set the default browser due to policy at
startup and during runtime.

BUG=101331
TEST=Manual testing performed


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=108059

[benwells, 2011-10-31 05:58:34]

Reproduced problem and fixed. Not sure if the call to set default browser in
response to a notification should also be changed; I'm assumnig it should but
have not tested this and haven't looked into how to exercise this code path.

[Mattias Nissler (ping if slow), 2011-10-31 07:58:08]

LGTM.

Regarding setting the default browser on PREF_CHANGED notification, you are
right with also moving that off the UI thread. If you like to test this, on
Linux you can flip the setting in the policy file (we have a watch on it) and
wait 5 seconds, on windows you just modify the registry key and run gpupdate to
trigger a group policy notification that Chrome catches.

[commit-bot: I haz the power, 2011-11-01 00:20:16]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/benwells@chromium.org/8409004/1

[commit-bot: I haz the power, 2011-11-01 02:02:13]

Change committed as 108059