Restructure the the pump for nested loops.

Change our work dispatching to be based around an event source.  This will allow us to still participate when a message loop is pumped by outside code (nested message loops).

Review URL: http://codereview.chromium.org/10854

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@5331 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed