monorail is buggy.

Deleted: Screen Shot 2017-06-21 at 2.13.11 PM.png 119 KB

	Screen Shot 2017-06-21 at 2.13.11 PM.png 119 KB View Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4247d81a3b3dd4f3f697543c7b818ed8669e5cac

commit 4247d81a3b3dd4f3f697543c7b818ed8669e5cac
Author: jif <jif@chromium.org>
Date: Thu Jun 22 01:45:34 2017

Stop re-adding subviews to keyboard accessory view.

With this CL the subviews are added only once.
Also, this CL enables the experimental keyboard accessory view on iPad, as
described in step 1 of
https://docs.google.com/document/d/1pWfwHEeCNeWgkDjawJiDoEf93gkDV9usINcYDyXvwcY

BUG= 735569 

Review-Url: https://codereview.chromium.org/2953613002
Cr-Commit-Position: refs/heads/master@{#481397}

[modify] https://crrev.com/4247d81a3b3dd4f3f697543c7b818ed8669e5cac/ios/chrome/browser/ui/toolbar/new_keyboard_accessory_view.h
[modify] https://crrev.com/4247d81a3b3dd4f3f697543c7b818ed8669e5cac/ios/chrome/browser/ui/toolbar/new_keyboard_accessory_view.mm
[modify] https://crrev.com/4247d81a3b3dd4f3f697543c7b818ed8669e5cac/ios/chrome/browser/ui/toolbar/web_toolbar_controller.mm