Add support for asynchronous event notification to the observatory.

Add support for asynchronous event notification to the observatory.

Implement "isolate pause" notifications.

R=johnmccutchan@google.com

Committed: https://code.google.com/p/dart/source/detail?r=37841

[turnidge, 2014-06-26 21:27:46]

https://codereview.chromium.org/340443006/diff/20001/runtime/bin/vmservice/cl...
File runtime/bin/vmservice/client/lib/src/app/application.dart (right):

https://codereview.chromium.org/340443006/diff/20001/runtime/bin/vmservice/cl...
runtime/bin/vmservice/client/lib/src/app/application.dart:257: vm = new
WebSocketVM() {
I recall that this broke something last time I changed this, but I don't
remember what it was...

[Cutch, 2014-06-27 16:03:49]

https://codereview.chromium.org/340443006/diff/20001/runtime/bin/vmservice/cl...
File runtime/bin/vmservice/client/lib/src/app/application.dart (right):

https://codereview.chromium.org/340443006/diff/20001/runtime/bin/vmservice/cl...
runtime/bin/vmservice/client/lib/src/app/application.dart:257: vm = new
WebSocketVM() {
On 2014/06/26 21:27:46, turnidge wrote:
> I recall that this broke something last time I changed this, but I don't
> remember what it was...

This breaks clicking the Observatory link to reconnect. My new WebSocketVM
solves this problem.

https://codereview.chromium.org/340443006/diff/20001/runtime/bin/vmservice/cl...
File runtime/bin/vmservice/client/lib/src/service/object.dart (right):

https://codereview.chromium.org/340443006/diff/20001/runtime/bin/vmservice/cl...
runtime/bin/vmservice/client/lib/src/service/object.dart:213: void
postEventMessage(String eventMessage) {
Why isn't the event just upgraded like other service objects?

https://codereview.chromium.org/340443006/diff/20001/runtime/bin/vmservice/cl...
runtime/bin/vmservice/client/lib/src/service/object.dart:806:
vm.events.add(event);
Why do we synthesize a resume event every time we update an isolate?

[turnidge, 2014-06-27 18:15:07]

https://codereview.chromium.org/340443006/diff/20001/runtime/bin/vmservice/cl...
File runtime/bin/vmservice/client/lib/src/app/application.dart (right):

https://codereview.chromium.org/340443006/diff/20001/runtime/bin/vmservice/cl...
runtime/bin/vmservice/client/lib/src/app/application.dart:257: vm = new
WebSocketVM() {
On 2014/06/27 16:03:49, Cutch wrote:
> On 2014/06/26 21:27:46, turnidge wrote:
> > I recall that this broke something last time I changed this, but I don't
> > remember what it was...
> 
> This breaks clicking the Observatory link to reconnect. My new WebSocketVM
> solves this problem.

Ok, good.

https://codereview.chromium.org/340443006/diff/20001/runtime/bin/vmservice/cl...
File runtime/bin/vmservice/client/lib/src/service/object.dart (right):

https://codereview.chromium.org/340443006/diff/20001/runtime/bin/vmservice/cl...
runtime/bin/vmservice/client/lib/src/service/object.dart:213: void
postEventMessage(String eventMessage) {
On 2014/06/27 16:03:49, Cutch wrote:
> Why isn't the event just upgraded like other service objects?

I don't understand.  Let's chat in person.

https://codereview.chromium.org/340443006/diff/20001/runtime/bin/vmservice/cl...
runtime/bin/vmservice/client/lib/src/service/object.dart:806:
vm.events.add(event);
On 2014/06/27 16:03:49, Cutch wrote:
> Why do we synthesize a resume event every time we update an isolate?

I was using a fake resume event to clear out any pause notifications that were
currently showing.  There really isn't an IsolateResumed event at all from the
VM.

This was a bit clumsy so I have removed it.  Now I just call removePauseEvents
directly from isolate_summary.dart when the resume request completes.  I forgot
that I added access to "app" from all observatory elements, so this is more
direct.

[Cutch, 2014-06-27 20:21:42]

lgtm

[turnidge, 2014-06-30 22:46:45]

Committed patchset #5 manually as r37841 (presubmit successful).