Fix for HTTP2 request hanging bug.

Fix for HTTP2 request hanging bug.

If, when a socket request completed asynchronously, the next
socket request in the queue failed synchronously,
ClientSocketPoolBase wouldn't continue to try to service other
socket requests in the queue.

As a result, the socket pools could end up with pending connect
requests and free socket slots, but no ConnectJobs would be made
to service them, if this happened 6 times in a row to a socket
group.

This was a relatively obscure issue, until H2 started depending
on this path for sharing sessions when different domains map to
the same IP.

BUG=723748
Review-Url: https://codereview.chromium.org/2888623011
Cr-Original-Commit-Position: refs/heads/master@{#472952}
Review-Url: https://codereview.chromium.org/2896883002 .
Cr-Commit-Position: refs/branch-heads/3071@{#654}
Cr-Branched-From: a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed: https://chromium.googlesource.com/chromium/src/+/ef63c09a56bf127df9990b3e7412f543b4733b0b

[mmenke, 2017-05-22 16:27:06]

Description was changed from

==========
Fix for HTTP2 request hanging bug.

If, when a socket request completed asynchronously, the next
socket request in the queue failed synchronously,
ClientSocketPoolBase wouldn't continue to try to service other
socket requests in the queue.

As a result, the socket pools could end up with pending connect
requests and free socket slots, but no ConnectJobs would be made
to service them, if this happened 6 times in a row to a socket
group.

This was a relatively obscure issue, until H2 started depending
on this path for sharing sessions when different domains map to
the same IP.

BUG=723748

Review-Url: https://codereview.chromium.org/2888623011
Cr-Commit-Position: refs/heads/master@{#472952}
(cherry picked from commit 9d72fe409a214856ec4d9700105b4664bb4c0861)
==========

to

==========
Fix for HTTP2 request hanging bug.

If, when a socket request completed asynchronously, the next
socket request in the queue failed synchronously,
ClientSocketPoolBase wouldn't continue to try to service other
socket requests in the queue.

As a result, the socket pools could end up with pending connect
requests and free socket slots, but no ConnectJobs would be made
to service them, if this happened 6 times in a row to a socket
group.

This was a relatively obscure issue, until H2 started depending
on this path for sharing sessions when different domains map to
the same IP.

BUG=723748

Review-Url: https://codereview.chromium.org/2888623011
Cr-Original-Commit-Position: refs/heads/master@{#472952}
Review-Url: https://codereview.chromium.org/2896883002 .
Cr-Commit-Position: refs/branch-heads/3071@{#654}
Cr-Branched-From:
a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed:
https://chromium.googlesource.com/chromium/src/+/ef63c09a56bf127df9990b3e7412...
==========

[mmenke, 2017-05-22 16:27:08]

Committed patchset #1 (id:1) manually as
ef63c09a56bf127df9990b3e7412f543b4733b0b.