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This updates the illustration and shows it for all dialog types except
the error dialog. The illustration is shown behind the dialog close
button above the title.

The BubbleFrameView is updated to support this illustration by adding a
header view. This view is similar to the existing footnote view and is
shown at the top of the dialog, above the title and behind the close
button.

Bug: 993378
Change-Id: I9d236557c2a3f31197441666e5aae526306e00cd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1778545Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Commit-Queue: Richard Knoll <knollr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#693614}