Track when QUIC connections are application limited. Protected by quic_enable_app_limited_check.

Track when QUIC connections are application limited. Protected by quic_enable_app_limited_check.

This CL notifies the congestion control algorithm when the connection
has no outstanding data to send. No behavior change is expected.

Merge internal change: 129351671

R=rch@chromium.org
BUG=

[danzh1, 2016-08-09 16:54:44]

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

[commit-bot: I haz the power, 2016-08-09 16:55:32]

Dry run: 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, 2016-08-09 17:00:40]

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

[commit-bot: I haz the power, 2016-08-09 17:00:41]

Dry run: Try jobs failed on following builders:
  cast_shell_linux on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/cast_shell_linu...)
  linux_chromium_asan_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_chromeos_compile_dbg_ng on master.tryserver.chromium.linux
(JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Ryan Hamilton, 2016-08-09 19:14:26]

lgtm

[danzh1, 2016-08-10 15:27:21]

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

[commit-bot: I haz the power, 2016-08-10 15:27:41]

Dry run: 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, 2016-08-10 15:34:48]

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

[commit-bot: I haz the power, 2016-08-10 15:34:49]

Dry run: Try jobs failed on following builders:
  ios-device on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-device/builds...)

[danzh1, 2016-08-10 19:08:30]

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

[commit-bot: I haz the power, 2016-08-10 19:09:20]

Dry run: 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, 2016-08-10 21:15:15]

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

[commit-bot: I haz the power, 2016-08-10 21:15:16]

Dry run: This issue passed the CQ dry run.