Instrumenting read callbacks to find jank in TCPSocketWin::Core::ReadDelegate::OnObjectSignaled

Instrumenting read callbacks to find jank in TCPSocketWin::Core::ReadDelegate::OnObjectSignaled.

See the bug.

I was told that one of the pieces of code that could cause jank is the callback invoked in IO thread once the read on a socket is complete. I'm not familiar with the code, and I instrumented places that look relevant; feel free to suggest adding or removing the instrumentation.

BUG=418183
TBR=asanka@chromium.org

Committed: https://crrev.com/06b0b7030916fd66381d0c547c5916c1d0934161
Cr-Commit-Position: refs/heads/master@{#299176}

[vadimt, 2014-10-08 01:29:23]

vadimt@chromium.org changed reviewers:
+ asanka@chromium.org

[vadimt, 2014-10-08 01:29:23]

asanka@, please provide OWNER's approval

[vadimt, 2014-10-09 19:24:35]

vadimt@chromium.org changed reviewers:
- asanka@chromium.org

[vadimt, 2014-10-09 19:28:36]

vadimt@chromium.org changed reviewers:
+ agl@chromium.org

[vadimt, 2014-10-09 19:28:36]

agl@, could you provide OWNER's approval (previous reviewer is currently
unavailable)?

[vadimt, 2014-10-10 19:31:07]

The CQ bit was checked by vadimt@chromium.org

[commit-bot: I haz the power, 2014-10-10 19:32:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/637733002/1

[commit-bot: I haz the power, 2014-10-10 20:28:52]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-10 20:29:55]

Patchset 1 (id:??) landed as
https://crrev.com/06b0b7030916fd66381d0c547c5916c1d0934161
Cr-Commit-Position: refs/heads/master@{#299176}

[agl, 2014-10-10 20:39:40]

lgtm