Replace the linked_hash_map used by the BandwidthSampler with a deque. Protected by FLAGS_quic_rel…

Replace the linked_hash_map used by the BandwidthSampler with a deque.  Protected by FLAGS_quic_reloadable_flag_quic_faster_bandwidth_sampler.

Merge internal change: 156575470

R=rch@chromium.org
BUG=

[ianswett, 2017-05-23 20:19:55]

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

[commit-bot: I haz the power, 2017-05-23 20:20:42]

Dry run: CQ is trying da patch.

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

[Ryan Hamilton, 2017-05-23 20:28:13]

lgtm

[commit-bot: I haz the power, 2017-05-23 20:35:46]

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

[commit-bot: I haz the power, 2017-05-23 20:35:47]

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...)
  ios-simulator on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-simulator/bui...)
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)