Move the tab-lifetime handling functionality out of ActiveTabPermissionGranter
and into a new class TabCapabilityTracker, to make room for web connectable
incognito support for apps.

BUG=305394
R=mpcomplete@chromium.org

Review URL: https://codereview.chromium.org/27604003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229235 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229235
Removed the pixel tests from content_browsertests.

Test has been replaced by a Telemetry-driver equivalent

BUG=278398
R=kbr@chromium.org, piman@chromium.org

Review URL: https://codereview.chromium.org/26647003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229236 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229236