Move PageTransition into content namespace. While I'm touching all these files, I've also updated it to use the enum naming convention in the Content API.

BUG=98716
Review URL: http://codereview.chromium.org/8253002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@105254 0039d316-1c4b-4281-b951-d872f2087c98
309 files changed