Move WebContents internals to use the new callbacks.

BUG=714018

Change-Id: I7adfe8e440d29b4f775535a9942e2354d076a9d3
Reviewed-on: https://chromium-review.googlesource.com/976656
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#545525}
2 files changed