Fix some service protocol isolate lifecycle races

Fix some service protocol isolate life cycle races that were discovered by the Flutter testing tool.

Fixes #25902

Issue #1

Assuming --pause-isolates-on-start, there is a window of time after an isolate is made runnable and before it pauses at the first message that we say the isolate is "resumed".

- Fix issue #1 by claiming the isolate is paused on start if it will eventually pause on start.
- Also, handle the resume command for this state by clearing the 'should pause on start' bit.

Issue #2

Before an isolate is made runnable we say the isolate is "resumed".

- Fix issue #2 by introducing a new pause event "None".

R=turnidge@google.com

Committed: https://github.com/dart-lang/sdk/commit/49dc7e557b74085d60c9b26cf806d3b73899972e

[Cutch, 2016-03-02 23:33:45]

Description was changed from

==========
Fix some service protocol isolate lifecycle races

BUG=
==========

to

==========
Fix some service protocol isolate life cycle races that were discovered by the
Flutter testing tool.

Issue #1

Assuming --pause-isolates-on-start, there is a window of time after an isolate
is made runnable and before it pauses at the first message that we say the
isolate is "resumed". 

- Fix issue #1 by claiming the isolate is paused on start if it will eventually
pause on start.
- Also, handle the resume command for this state by clearing the 'should pause
on start' bit.

Issue #2

Before an isolate is made runnable we say the isolate is "resumed".

- Fix issue #2 by introducing a new pause event "PauseUntilRunnable".
==========

[Cutch, 2016-03-02 23:33:46]

johnmccutchan@google.com changed reviewers:
+ turnidge@google.com

[Cutch, 2016-03-02 23:34:29]

Todd,

This is somewhat exploratory. Let's discuss this in the morning.

John

[Cutch, 2016-03-02 23:55:29]

Description was changed from

==========
Fix some service protocol isolate life cycle races that were discovered by the
Flutter testing tool.

Issue #1

Assuming --pause-isolates-on-start, there is a window of time after an isolate
is made runnable and before it pauses at the first message that we say the
isolate is "resumed". 

- Fix issue #1 by claiming the isolate is paused on start if it will eventually
pause on start.
- Also, handle the resume command for this state by clearing the 'should pause
on start' bit.

Issue #2

Before an isolate is made runnable we say the isolate is "resumed".

- Fix issue #2 by introducing a new pause event "PauseUntilRunnable".
==========

to

==========
Fix some service protocol isolate life cycle races that were discovered by the
Flutter testing tool.

Fixes #25902

Issue #1

Assuming --pause-isolates-on-start, there is a window of time after an isolate
is made runnable and before it pauses at the first message that we say the
isolate is "resumed". 

- Fix issue #1 by claiming the isolate is paused on start if it will eventually
pause on start.
- Also, handle the resume command for this state by clearing the 'should pause
on start' bit.

Issue #2

Before an isolate is made runnable we say the isolate is "resumed".

- Fix issue #2 by introducing a new pause event "PauseUntilRunnable".
==========

[turnidge, 2016-03-03 17:15:01]

lgtm but let's consider changing the event name.  Currently leaning to
ServiceEvent.kNone...

https://codereview.chromium.org/1756393002/diff/20001/runtime/observatory/lib...
File runtime/observatory/lib/src/app/application.dart (right):

https://codereview.chromium.org/1756393002/diff/20001/runtime/observatory/lib...
runtime/observatory/lib/src/app/application.dart:112: case
ServiceEvent.kPauseUntilRunnable:
We will never receive this event.  Maybe make it its own case which asserts not
received or move to default case?

https://codereview.chromium.org/1756393002/diff/20001/runtime/observatory/lib...
File runtime/observatory/lib/src/elements/debugger.dart (right):

https://codereview.chromium.org/1756393002/diff/20001/runtime/observatory/lib...
runtime/observatory/lib/src/elements/debugger.dart:1527: if (event.kind ==
ServiceEvent.kPauseUntilRunnable) {
I'm debating this name a bit.

It could just be ServiceEvent.kNotRunnable or ServiceEvent.kPauseNotRunnable or
maybe even ServiceEvent.kNone (no event ever sent).

[Cutch, 2016-03-03 19:22:00]

https://codereview.chromium.org/1756393002/diff/20001/runtime/observatory/lib...
File runtime/observatory/lib/src/app/application.dart (right):

https://codereview.chromium.org/1756393002/diff/20001/runtime/observatory/lib...
runtime/observatory/lib/src/app/application.dart:112: case
ServiceEvent.kPauseUntilRunnable:
On 2016/03/03 17:15:01, turnidge wrote:
> We will never receive this event.  Maybe make it its own case which asserts
not
> received or move to default case?

Done.

https://codereview.chromium.org/1756393002/diff/20001/runtime/observatory/lib...
File runtime/observatory/lib/src/elements/debugger.dart (right):

https://codereview.chromium.org/1756393002/diff/20001/runtime/observatory/lib...
runtime/observatory/lib/src/elements/debugger.dart:1527: if (event.kind ==
ServiceEvent.kPauseUntilRunnable) {
On 2016/03/03 17:15:01, turnidge wrote:
> I'm debating this name a bit.
> 
> It could just be ServiceEvent.kNotRunnable or ServiceEvent.kPauseNotRunnable
or
> maybe even ServiceEvent.kNone (no event ever sent).

ServiceEvent.kNone.

Done.

[Cutch, 2016-03-03 19:30:34]

Description was changed from

==========
Fix some service protocol isolate life cycle races that were discovered by the
Flutter testing tool.

Fixes #25902

Issue #1

Assuming --pause-isolates-on-start, there is a window of time after an isolate
is made runnable and before it pauses at the first message that we say the
isolate is "resumed". 

- Fix issue #1 by claiming the isolate is paused on start if it will eventually
pause on start.
- Also, handle the resume command for this state by clearing the 'should pause
on start' bit.

Issue #2

Before an isolate is made runnable we say the isolate is "resumed".

- Fix issue #2 by introducing a new pause event "PauseUntilRunnable".
==========

to

==========
Fix some service protocol isolate life cycle races that were discovered by the
Flutter testing tool.

Fixes #25902

Issue #1

Assuming --pause-isolates-on-start, there is a window of time after an isolate
is made runnable and before it pauses at the first message that we say the
isolate is "resumed". 

- Fix issue #1 by claiming the isolate is paused on start if it will eventually
pause on start.
- Also, handle the resume command for this state by clearing the 'should pause
on start' bit.

Issue #2

Before an isolate is made runnable we say the isolate is "resumed".

- Fix issue #2 by introducing a new pause event "None".
==========

[Cutch, 2016-03-03 19:30:46]

Description was changed from

==========
Fix some service protocol isolate life cycle races that were discovered by the
Flutter testing tool.

Fixes #25902

Issue #1

Assuming --pause-isolates-on-start, there is a window of time after an isolate
is made runnable and before it pauses at the first message that we say the
isolate is "resumed". 

- Fix issue #1 by claiming the isolate is paused on start if it will eventually
pause on start.
- Also, handle the resume command for this state by clearing the 'should pause
on start' bit.

Issue #2

Before an isolate is made runnable we say the isolate is "resumed".

- Fix issue #2 by introducing a new pause event "None".
==========

to

==========
Fix some service protocol isolate life cycle races that were discovered by the
Flutter testing tool.

Fixes #25902

Issue #1

Assuming --pause-isolates-on-start, there is a window of time after an isolate
is made runnable and before it pauses at the first message that we say the
isolate is "resumed".

- Fix issue #1 by claiming the isolate is paused on start if it will eventually
pause on start.
- Also, handle the resume command for this state by clearing the 'should pause
on start' bit.

Issue #2

Before an isolate is made runnable we say the isolate is "resumed".

- Fix issue #2 by introducing a new pause event "None".

R=turnidge@google.com

Committed:
https://github.com/dart-lang/sdk/commit/49dc7e557b74085d60c9b26cf806d3b73899972e
==========

[Cutch, 2016-03-03 19:30:47]

Committed patchset #4 (id:60001) manually as
49dc7e557b74085d60c9b26cf806d3b73899972e (presubmit successful).