Be more strict about attributes in sky-binder.

Be more strict about attributes in sky-binder.

Instead of making all the built in attributes be global we match them to the
elements they actually apply to. I also removed a bunch of attributes that no
longer work in Sky (but haven't been removed from HTMLAttributeNames.in) yet,
or which we plan to remove.

I also removed the title property from HTMLElement. The <sky-box> widget forgot
to declare its title attribute and no error was generated because of the title
property existing on all elements. Sky doesn't have this so lets remove the API
now and clean up the C++ later.

R=ojan@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/38667f7d9ea2d61a61ab7e9fda837ed17f893c56

[ojan, 2015-01-16 20:32:54]

ojan@chromium.org changed reviewers:
+ ojan@chromium.org

[ojan, 2015-01-16 20:32:54]

lgtm

[esprehn, 2015-01-16 22:41:11]

Committed patchset #2 (id:20001) manually as
38667f7d9ea2d61a61ab7e9fda837ed17f893c56 (presubmit successful).