The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6bcc66a0b16cc674d32c856f0251fa3ba100e41a

commit 6bcc66a0b16cc674d32c856f0251fa3ba100e41a
Author: Yuwei Huang <yuweih@chromium.org>
Date: Sun Oct 01 07:46:28 2017

[CRD iOS] Host view a11y improvements

* Allow the host view to accept and handle raw gestures when VoiceOver
  is on.
* Add a four-finger-tap gesture to show the menu.
* Add an announcement when the host view is shown to let the user know
  how they could pop up the menu.

Bug:  769882 
Change-Id: Ibcdfa81673ccabd43bddebcd320adc727b0ca29f
Reviewed-on: https://chromium-review.googlesource.com/691294
Reviewed-by: Scott Nichols <nicholss@chromium.org>
Commit-Queue: Yuwei Huang <yuweih@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505513}
[modify] https://crrev.com/6bcc66a0b16cc674d32c856f0251fa3ba100e41a/remoting/ios/app/host_view_controller.mm
[modify] https://crrev.com/6bcc66a0b16cc674d32c856f0251fa3ba100e41a/remoting/ios/client_gestures.h
[modify] https://crrev.com/6bcc66a0b16cc674d32c856f0251fa3ba100e41a/remoting/ios/client_gestures.mm
[modify] https://crrev.com/6bcc66a0b16cc674d32c856f0251fa3ba100e41a/remoting/resources/remoting_strings.grd

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/84faae3a0b51668e2d1bdfdf12b1f6dfc1d3ceab

commit 84faae3a0b51668e2d1bdfdf12b1f6dfc1d3ceab
Author: Yuwei Huang <yuweih@chromium.org>
Date: Tue Oct 03 19:39:19 2017

[CRD iOS] Post dynamic announcement when the host is connected

According to the a11y spec, the host connected announcement should not
interrupt with the current announcing speech.

This CL adds a method for posting a "dynamic" announcement
asynchronously and use it to post the host connected announcement. It
also moves the call to ViewDidLoad so that it will be announced
exactly once.

Bug:  769882 
Change-Id: I5bc02d7b9426d2334398f6610bc12adb6d8ae71c
Reviewed-on: https://chromium-review.googlesource.com/696263
Commit-Queue: Yuwei Huang <yuweih@chromium.org>
Reviewed-by: Scott Nichols <nicholss@chromium.org>
Cr-Commit-Position: refs/heads/master@{#506142}
[modify] https://crrev.com/84faae3a0b51668e2d1bdfdf12b1f6dfc1d3ceab/remoting/ios/app/host_view_controller.mm
[modify] https://crrev.com/84faae3a0b51668e2d1bdfdf12b1f6dfc1d3ceab/remoting/ios/app/view_utils.h
[modify] https://crrev.com/84faae3a0b51668e2d1bdfdf12b1f6dfc1d3ceab/remoting/ios/app/view_utils.mm