Added metrics for Tab status when app goes background.

Added two new additional reasons to TabStatus enum.

Review URL: https://codereview.chromium.org/139303010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246211 0039d316-1c4b-4281-b951-d872f2087c98
ash: Move LauncherItemType and LauncherItemStatus over shelf_item_types.h

And also rename them to ShelfItem*

BUG=248353
TEST=None, no functional changes
R=jamescook@chromium.org,harrym@chromium.org

Review URL: https://codereview.chromium.org/143123004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246212 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246212
New home page for developer.chrome.com

And pillar pages for DevTools, Multi-device, and Platform.

Review URL: https://codereview.chromium.org/140743011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246213 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246213