The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/15973c3f1ac558b3b3eed70a1a7a3ed256528a65

commit 15973c3f1ac558b3b3eed70a1a7a3ed256528a65
Author: tbansal <tbansal@chromium.org>
Date: Wed May 10 18:40:44 2017

Expose changes in the network quality to the renderers

A network quality observer owned by IOThread has been added. It listens
to the network quality changes and notifies renderers on the UI thread
using mojo. This is similar to how content::BrowserOnlineStateObserver
listens to the connection type changes.

BUG= 719511 

Review-Url: https://codereview.chromium.org/2857093002
Cr-Commit-Position: refs/heads/master@{#470654}

[modify] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/chrome/browser/io_thread.cc
[modify] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/chrome/browser/io_thread.h
[modify] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/content/browser/BUILD.gn
[add] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/content/browser/net/network_quality_observer_impl.cc
[add] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/content/browser/net/network_quality_observer_impl.h
[modify] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/content/browser/net_info_browsertest.cc
[modify] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/content/common/renderer.mojom
[modify] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/content/public/browser/BUILD.gn
[add] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/content/public/browser/network_quality_observer_factory.h
[modify] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/content/renderer/render_thread_impl.cc
[modify] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/content/renderer/render_thread_impl.h
[modify] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/net/nqe/network_quality_estimator.h
[modify] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/net/nqe/network_quality_estimator_test_util.cc
[modify] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/net/nqe/network_quality_estimator_test_util.h
[modify] https://crrev.com/15973c3f1ac558b3b3eed70a1a7a3ed256528a65/tools/metrics/histograms/histograms.xml