Adding factory constructors to all classes to suppress missing generative constructor warnings.
Adding a throw to Dartium's base DOM class to prevent construction of native objects.
This also includes the changes necessary to make all DOM types abstract, but I'm running into a dart2js issue which is preventing that.
BUG=
R=vsm@google.com
Review URL: https://codereview.chromium.org//17063007
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@24241 260f80e4-7a28-3924-810f-c04153c831b5
Basically a number of our platform checks are only accessible from dart:html and not other libs. Moved Device class over to html_common and added more platform logic which was distributed elsewhere.
Also fixing up Device to cache the platform checks.
BUG=
Review URL: https://codereview.chromium.org//12541020
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@19833 260f80e4-7a28-3924-810f-c04153c831b5
blois@google.com