GitLab

* Moved parts->PostMainMessageLoopRun call from PostDestroyThreads to the right place (PostMainMessageLoopRun() method)
* Renamed Shell::DeleteInstanceForTesting to DeleteInstance as this is no longer for testing.

BUG=106070
TEST=browser_tests on aura will not crash as described in the bug

Review URL: http://codereview.chromium.org/8774029

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@112836 0039d316-1c4b-4281-b951-d872f2087c98