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* Makes it so that infobars hide when scrolling the page and
  return at the top of the page.

* SwipableOverlayView is now the base class of InfoBarContainer
  and now extends from ScrollLayout.

* Adds way to disable the SwipableOverlayView from being swiped
  away.

* AppBannerView (which is going away soon) is adjusted to account
  for the new ScrollLayout requirement of having only one child.

BUG=453170

Review URL: https://codereview.chromium.org/893483002

Cr-Commit-Position: refs/heads/master@{#313987}