Rip out phantom tabs and corresponding unit tests.

Also get rid of the type enum passed to TabReplacedAt since it can only be one option after phantom tabs are removed.

BUG=none
TEST=compile? good. pass tests? good.

Review URL: http://codereview.chromium.org/3539010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@61303 0039d316-1c4b-4281-b951-d872f2087c98
46 files changed