Fix for NPE when attempt to open Element with null Source.

R=brianwilkerson@google.com
BUG=

Review URL: https://codereview.chromium.org//660393003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41209 260f80e4-7a28-3924-810f-c04153c831b5
Reapply "Stop suppressing generation of bindings with Promise. Add some tests for DOM APIs that answer promises."

Fix static warning in storage_quota_test.

Fix status of fontface_loaded_test.

R=leafp@google.com

Review URL: https://codereview.chromium.org//658903005

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41210 260f80e4-7a28-3924-810f-c04153c831b5