Fix a Chrome browser crash which is seen during chrome frame reliability test runs.Based on the c...

Fix a Chrome browser crash which is seen during chrome frame reliability test runs.Based on the callstack it
occurs when the cookie completion callback map's singleton instance is torn down during shutdown. It looks
like there are unprocessed cookie request entries in the map which when deleted by the map destructor cause a crash.

Fix being attempted is to delete the cookie entries associated with the AutomationResourceMessageFilter instance
when we receive an OnChannelClosing notification.

Fixes bug http://code.google.com/p/chromium/issues/detail?id=87693

BUG=87693
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=90811

[robertshield, 2011-06-28 18:28:35]

LGTM, just one nit:

http://codereview.chromium.org/7273019/diff/1/chrome/browser/automation/autom...
File chrome/browser/automation/automation_resource_message_filter.cc (right):

http://codereview.chromium.org/7273019/diff/1/chrome/browser/automation/autom...
chrome/browser/automation/automation_resource_message_filter.cc:170: } else {
drop the else and increment callback_index only in a single location?