Fix tab backgrounding

This broke because an incompatible change was made to Process, and because there was no test that would catch it. I've fixed the underlying problem for both Linux and ChromeOS and made it testable.

BUG=102726
TEST=Added new RenderProcessHostTest.Backgrounding

Review URL: http://codereview.chromium.org/8506036

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@112712 0039d316-1c4b-4281-b951-d872f2087c98
6 files changed