Prepare RFHM for disabling swapped out state.

This CL ensures that RenderFrameHostManager doesn't create swapped out
RenderViewHosts when swapped out state is disabled. It should be creating
proxy objects instead.

BUG=357747

Review URL: https://codereview.chromium.org/1341003002

Cr-Commit-Position: refs/heads/master@{#348688}
1 file changed