RenderDocument: Prepare WebLocalFrameImpl::CreateProvisional.

The goal of RenderDocument is to make RenderFrameHost to have a
"document" semantic. RenderFrameHost are currently replaced by a new
one after each cross-process navigation. It needs now to be replaced
after each same-process navigation as well.

+ This CL makes WebLocalFrameImpl::CreateProvisional being able to take
a WebFrame instead of a WebRemoteFrame for |previous_web_frame|. In
the future, the |previous_web_frame| will be either a local or a remote
frame.

+ Rename "old" by "previous" for consistency with |previous_routing_id|.

Bug: 936696
Change-Id: I3de80b751125c473e90b3fab7e7af80dc476c973
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1523090
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#642445}
4 files changed