Removing redundant event streams.

Removing redundant event streams.

Basically removing the event stream providers from Document and Window for events which are also declared on Element. The streams themselves are still exposed, just that a single provider is now on Element.

Also removed MediaElement events from Window, as they are duplicative and should be accessed via the MediaElement provider.

I was also hoping that this would have some JS size benefits, but I'm not seeing any.


BUG=7860
Committed: https://code.google.com/p/dart/source/detail?r=17229

[sra1, 2013-01-17 11:20:05]

You are not seeing any size benefit because

(1) const EventStreamProvider<Event>('abort');
is the same immutable object not matter how many times you write it out in full.

(2) The static const constants get 'inlined' to their values. (dart2js does
leave unreferenced names in the generated code but that should go away:
https://code.google.com/p/dart/issues/detail?id=7568)

Given (1) I'm not sure this CL is worthwhile, but EventStreamProviders ever need
to be non-const, it would be.

LGTM if you want to keep the explicit sharing.