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I wasn't thinking and realized I need to get rid of the dependency on Browser IOThread, because the service process doesn't have one.
This means I can move this back to chrome/common, but I won't do that until you have finished your implementations.

BUG=NONE
TEST=BUILD

Review URL: http://codereview.chromium.org/6312007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@71961 0039d316-1c4b-4281-b951-d872f2087c98