Proper sequencing of _asyncStackTraceHelper in Kernel

Proper sequencing of _asyncStackTraceHelper in Kernel

This helper function was being called before its argument was
initialized so it was passing null.  Instead, it should be called
after its argument is initialized.

Because the initialization happens in Kernel code, it is simplest to
insert the call explicitly in Kernel code as well as part of the async
transformation.  This has the consequence that we now call the helper
function even when the flag causal_async_stacks is false.

Fixes #29771.

BUG=
R=aam@google.com, asiva@google.com

Committed: https://github.com/dart-lang/sdk/commit/0489249d29131ed7bf047485c74f557d88eb9974

[Kevin Millikin (Google), 2017-06-13 15:56:18]

kmillikin@google.com changed reviewers:
+ aam@google.com, asiva@google.com

[aam, 2017-06-13 17:20:39]

lgtm, thanks!

And it does fix running Flutter gallery with '--causal_async_traces'.

[aam, 2017-06-13 17:21:13]

On 2017/06/13 17:20:39, aam wrote:
> lgtm, thanks!
> 
> And it does fix running Flutter gallery with '--causal_async_traces'.

I meant '--causal_async_stacks'.

[siva, 2017-06-13 21:49:50]

lgtm

[Kevin Millikin (Google), 2017-06-19 14:53:03]

Description was changed from

==========
Proper sequencing of _asyncStackTraceHelper in Kernel

This helper function was being called before its argument was
initialized so it was passing null.  Instead, it should be called
after its argument is initialized.

Because the initialization happens in Kernel code, it is simplest to
insert the call explicitly in Kernel code as well as part of the async
transformation.  This has the consequence that we now call the helper
function even when the flag causal_async_stacks is false.

Fixes #29771.

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

to

==========
Proper sequencing of _asyncStackTraceHelper in Kernel

This helper function was being called before its argument was
initialized so it was passing null.  Instead, it should be called
after its argument is initialized.

Because the initialization happens in Kernel code, it is simplest to
insert the call explicitly in Kernel code as well as part of the async
transformation.  This has the consequence that we now call the helper
function even when the flag causal_async_stacks is false.

Fixes #29771.

BUG=
R=aam@google.com, asiva@google.com

Committed:
https://github.com/dart-lang/sdk/commit/0489249d29131ed7bf047485c74f557d88eb9974
==========

[Kevin Millikin (Google), 2017-06-19 14:53:06]

Committed patchset #2 (id:20001) manually as
0489249d29131ed7bf047485c74f557d88eb9974 (presubmit successful).