Optimize StackTrace.current Eliminate redundant call to captureStackTrace and compute the stack tra…

Optimize StackTrace.current Eliminate redundant call to captureStackTrace and compute the stack trace without throwing an exception on more browsers.

BUG=
R=sra@google.com

Committed: https://github.com/dart-lang/sdk/commit/ac5a77e3a19850a561fd1d8fe6fdf89477c65993

[Jacob, 2017-01-30 23:31:35]

jacobr@google.com changed reviewers:
+ sra@google.com

[Jacob, 2017-01-30 23:31:36]

This should speedup runtime performance for Dart2JS applications that capture
async stack traces considerably.

The equivalent change in DDC improved performance of
some angular dart benchmarks by 35%
Expect performance improvement from this change may be
larger in FireFox, Safari, and Edge as previously an
exception was thrown and caught to capture stack traces
in those browsers.

[sra1, 2017-01-30 23:39:35]

lgtm

[Jacob, 2017-01-30 23:46:31]

Description was changed from

==========
Optimize StackTrace.current Eliminate redundant call to captureStackTrace and
compute the stack trace without throwing an exception on more browsers.

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

to

==========
Optimize StackTrace.current Eliminate redundant call to captureStackTrace and
compute the stack trace without throwing an exception on more browsers.

BUG=
R=sra@google.com

Committed:
https://github.com/dart-lang/sdk/commit/ac5a77e3a19850a561fd1d8fe6fdf89477c65993
==========

[Jacob, 2017-01-30 23:46:32]

Committed patchset #1 (id:1) manually as
ac5a77e3a19850a561fd1d8fe6fdf89477c65993 (presubmit successful).

[Jacob, 2017-02-03 19:20:19]

https://codereview.chromium.org/2667813002/diff/20001/sdk/lib/_internal/js_ru...
File sdk/lib/_internal/js_runtime/lib/core_patch.dart (right):

https://codereview.chromium.org/2667813002/diff/20001/sdk/lib/_internal/js_ru...
sdk/lib/_internal/js_runtime/lib/core_patch.dart:700: // Fallback if new
Error().stack does not exist.
Ignore this file. Unrelated