Fix the crashes in interactive_ui_tests on Linux.
Fix the crashes in interactive_ui_tests on Linux.

The cause is really subtle.  When I added a db_thread() in BrowserMain, that changed the order that threads were created at.  Since interactive ui tests don't run atexitmanager (I filed a bug to make them do), this cascaded into file_posix.cc's InFlightIO singelton caching the first IO MessageLoop pointer.  By fluke, previously each IO ML would have the exact same pointer value (must be a unique size for the allocator).  My change modified the construction order, so the second run would have a different ChromeThread (file) get the previous IO thread's ML pointer.  That led to the asserts.  I have added code to start the threads in a predictable manner for now.

BUG=25354
TEST=interactive_ui_tests in Linux stop crashing
Review URL: http://codereview.chromium.org/340017

git-svn-id: http://src.chromium.org/svn/trunk/src@30303 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: c722777431591944dca3631fe9135b8ef0d65263
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser