Removing GetDefaultProfile from the Bluetooth code

BUG=322682
TEST=covered by existing tests

Review URL: https://codereview.chromium.org/113463004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241458 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241458