Remove swapped-out usage in --site-per-process.
When navigating cross-process, we use swapped-out RenderFrameHost as placeholders. The goal is to replace this with RenderFrameProxyHost, which is already the case for all subframes, but not the main frame. The code is far along that this can be done now for the main frame as well.
This CL starts the path to removing the swapped-out RenderFrameHost concept by deleting the RenderFrameHost for the main frame on cross-process navigations and only keeping a RenderFrameProxyHost around. It is doing this for --site-per-process only, so all details can be fleshed out. Subsequent CL will remove the --site-per-process restriction and enable it in all modes of Chrome.
BUG=357747
Review URL: https://codereview.chromium.org/1142123002
Cr-Commit-Position: refs/heads/master@{#333100}
31 files changed
