Cleanup many APIs to use ProfileKeyedAPI.

This allows extra boilerplate BrowserContextKeyedServiceFactory code to be deleted.

In this CL: ActivityLog, ExtensionSyncEventObserver, RuntimeAPI, DeveloperPrivateAPI, BluetoothAPI, AutotestPrivateAPI.

BUG=179951
TBR=erg@chromium.org

Review URL: https://codereview.chromium.org/168253002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253928 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253928