This converts the CreateChildFrame synchronous method into two IPCs that
better match the current design of the APIs.
1) A routing ID (and frame tokens) are first allocated using
a new synchronous API.
2) The async API to create a child frame is then dispatched at the
FrameHost with the new routing ID.
BUG=993189
Change-Id: Iae5a31346b80bd5a5eaee8403a7e1b9b61fb5da0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2507511
Reviewed-by: Charlie Reis <creis@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Łukasz Anforowicz <lukasza@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824427}
4e60c23134