Update MediaStreamConstraintsAudioUtil unit tests.

Update MediaStreamConstraintsAudioUtil unit tests.

Use array elements instead of pointer values in comparisons involving
pointers to member functions.
One of these comparisons failed on Windows Debug and others are suspect
of failing on WinClang DLL builds.

BUG=736309
Review-Url: https://codereview.chromium.org/2958543002
Cr-Commit-Position: refs/heads/master@{#481932}
Committed: https://chromium.googlesource.com/chromium/src/+/964d2c65e8b24f15ddaeb18429b5ce1d3469d445

[Guido Urdaneta, 2017-06-23 11:28:01]

The CQ bit was checked by guidou@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-06-23 11:28:05]

Dry run: CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Guido Urdaneta, 2017-06-23 11:53:00]

guidou@chromium.org changed reviewers:
+ rnk@chromium.org

[Guido Urdaneta, 2017-06-23 11:53:01]

Hi, PTAL

[commit-bot: I haz the power, 2017-06-23 12:06:34]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-06-23 12:06:35]

Dry run: This issue passed the CQ dry run.

[Reid Kleckner, 2017-06-23 16:42:01]

Description was changed from

==========
Update MediaStreamConstraintsAudioUtil unit tests.

Use array elements instead of pointer values in comparisons involving
pointers to member functions.
One of these comparisons failed on Windows Debug and others are suspect
of failing on WinClang DLL builds.

BUG=736309
==========

to

==========
Update MediaStreamConstraintsAudioUtil unit tests.

Use array elements instead of pointer values in comparisons involving
pointers to member functions.
One of these comparisons failed on Windows Debug and others are suspect
of failing on WinClang DLL builds.

BUG=736309
==========

[Reid Kleckner, 2017-06-23 16:42:01]

rnk@chromium.org changed reviewers:
+ hans@chromium.org

[Reid Kleckner, 2017-06-23 16:50:07]

In general, I think relying function pointer and member pointer equality is
risky. I know of two things that can make it go wrong: DLLs and ICF. I haven't
figured out exactly what's happening here yet.

ICF (identical code/comdat folding) will merge identical inline functions, so
pointers to similar functions will compare equal at runtime. Yes, this is
non-conforming, but it's valuable enough that MSVC does it anyway. This is
enabled in Chrome release builds, and is probably not at fault here.

For DLLs, the Windows loader does not coalesce multiple symbols with the same
name across multiple DLLs. That's just not something it does. So, if you take
the address of the same inline function in two DLLs and pass them around, they
will not compare equal. The only way to make function pointer equality work is
if you pin the function to a particular DLL with dllexport/dllimport. That might
be the issue here, but it doesn't seem like it because all your member pointers
and comparisons seem to originate from the unit test file.

It's entirely possible that clang is doing something wrong here and we're making
the problem worse, but in general, we know function pointer equality doesn't
work well. I would recommend steering away from member function pointer equality
checks in the future.

[Reid Kleckner, 2017-06-23 16:51:12]

lgtm, let's try this.

[Reid Kleckner, 2017-06-23 16:51:16]

The CQ bit was checked by rnk@chromium.org

[commit-bot: I haz the power, 2017-06-23 16:51:26]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-06-23 16:56:33]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1498236676404340, "parent_rev":
"834eaab8e927945d5b0d9bb60282a1733d50256f", "commit_rev":
"964d2c65e8b24f15ddaeb18429b5ce1d3469d445"}

[commit-bot: I haz the power, 2017-06-23 16:56:45]

Description was changed from

==========
Update MediaStreamConstraintsAudioUtil unit tests.

Use array elements instead of pointer values in comparisons involving
pointers to member functions.
One of these comparisons failed on Windows Debug and others are suspect
of failing on WinClang DLL builds.

BUG=736309
==========

to

==========
Update MediaStreamConstraintsAudioUtil unit tests.

Use array elements instead of pointer values in comparisons involving
pointers to member functions.
One of these comparisons failed on Windows Debug and others are suspect
of failing on WinClang DLL builds.

BUG=736309

Review-Url: https://codereview.chromium.org/2958543002
Cr-Commit-Position: refs/heads/master@{#481932}
Committed:
https://chromium.googlesource.com/chromium/src/+/964d2c65e8b24f15ddaeb18429b5...
==========

[commit-bot: I haz the power, 2017-06-23 16:56:47]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/964d2c65e8b24f15ddaeb18429b5...

[Reid Kleckner, 2017-06-23 17:31:52]

I've debugged this a bit. It's definitely a clang bug. We've fixed one like it
before. I'll file it and update this for the curious.

[Reid Kleckner, 2017-06-23 17:35:59]

On 2017/06/23 17:31:52, Reid Kleckner wrote:
> I've debugged this a bit. It's definitely a clang bug. We've fixed one like it
> before. I'll file it and update this for the curious.

Filed as https://bugs.llvm.org/show_bug.cgi?id=33570