Refactor RFHM::InitRenderView to take in RenderFrameProxyHost parameter

This CL is picking only the refactoring part of https://codereview.chromium.org/1408743005/,
which contained change in behavior as well. It was reverted due to a
potential memory leak, so I am landing the refactoring and the actual
fix separately now.

BUG=357747, 544271

Review URL: https://codereview.chromium.org/1415303002

Cr-Commit-Position: refs/heads/master@{#355566}
2 files changed