The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e3c624d2815978ae0e0e8b52799e32e6bed9f5ec

commit e3c624d2815978ae0e0e8b52799e32e6bed9f5ec
Author: Yuwei Huang <yuweih@chromium.org>
Date: Thu Sep 28 00:40:45 2017

[CRD iOS] Pull to refresh and Chromium implementation

Currently MaterialComponents hasn't implemented the pull-to-refresh
functionality, but internally we do have a component to provide
Googlewide conforming pull-to-refresh UX.

This CL:
* Creates a RefreshControlProvider framework for providing pull-to-
  refresh UI depending on the app variant.
* Provides the Chromium implementation, i.e. using the standard
  UIRefreshControl, the flower-like spinning wheel.
* Modifies other code to use RefreshControlProviderand cleans up the
  old refresh button.

Once MaterialComponents implements the pull-to-refresh component,
we could start using it and get rid of the RefreshControlProvider.

Bug:  768480 
Change-Id: Ibfc519a5df620f0ecf7dd6250f726c9a0efa096a
Reviewed-on: https://chromium-review.googlesource.com/680115
Reviewed-by: Scott Nichols <nicholss@chromium.org>
Commit-Queue: Yuwei Huang <yuweih@chromium.org>
Cr-Commit-Position: refs/heads/master@{#504823}
[modify] https://crrev.com/e3c624d2815978ae0e0e8b52799e32e6bed9f5ec/remoting/ios/app/BUILD.gn
[modify] https://crrev.com/e3c624d2815978ae0e0e8b52799e32e6bed9f5ec/remoting/ios/app/app_initializer_chromium.mm
[modify] https://crrev.com/e3c624d2815978ae0e0e8b52799e32e6bed9f5ec/remoting/ios/app/host_fetching_view_controller.h
[modify] https://crrev.com/e3c624d2815978ae0e0e8b52799e32e6bed9f5ec/remoting/ios/app/host_fetching_view_controller.mm
[add] https://crrev.com/e3c624d2815978ae0e0e8b52799e32e6bed9f5ec/remoting/ios/app/refresh_control_provider.h
[add] https://crrev.com/e3c624d2815978ae0e0e8b52799e32e6bed9f5ec/remoting/ios/app/refresh_control_provider.mm
[add] https://crrev.com/e3c624d2815978ae0e0e8b52799e32e6bed9f5ec/remoting/ios/app/refresh_control_provider_chromium.h
[add] https://crrev.com/e3c624d2815978ae0e0e8b52799e32e6bed9f5ec/remoting/ios/app/refresh_control_provider_chromium.mm
[modify] https://crrev.com/e3c624d2815978ae0e0e8b52799e32e6bed9f5ec/remoting/ios/app/remoting_theme.h
[modify] https://crrev.com/e3c624d2815978ae0e0e8b52799e32e6bed9f5ec/remoting/ios/app/remoting_theme.mm
[modify] https://crrev.com/e3c624d2815978ae0e0e8b52799e32e6bed9f5ec/remoting/ios/app/remoting_view_controller.mm

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chrome/ios_internal.git/+/a9ff792d13b0a2dc08fdd73d023159fb4f09b083

commit a9ff792d13b0a2dc08fdd73d023159fb4f09b083
Author: Yuwei Huang <yuweih@chromium.org>
Date: Thu Sep 28 03:14:31 2017