Make RenderFrameHostManager swap RenderFrameHosts, not RenderViewHosts.

Make RenderFrameHostManager swap RenderFrameHosts, not RenderViewHosts.

We still only have a RFHM for the main frame and not subframes, unless
the --site-per-process flag is passed. To external callers, RFHM is
still effectively swapping RenderViewHosts.

RenderFrameHosts now indirectly keep their RenderViewHosts alive.

Second attempt, after fixing memory leak from http://crrev.com/241151.

R=nasko@chromium.org
TBR=jam@chromium.org
BUG=314791
TEST=No visible behavior change.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=241423

[Charlie Reis, 2013-12-17 22:40:21]

Argh!  Somehow my git rebase caused https://codereview.chromium.org/108483008/
to commit *only* the memory leak fix and not the rest of the CL.

Nasko, can you give this a quick sanity check so I can commit the rest?

https://codereview.chromium.org/117693002/diff/1/content/browser/web_contents...
File content/browser/web_contents/web_contents_impl_unittest.cc (right):

https://codereview.chromium.org/117693002/diff/1/content/browser/web_contents...
content/browser/web_contents/web_contents_impl_unittest.cc:183: protected:
Note: The CreateRenderViewHost method has already been removed in
http://crrev.com/241363, so the memory leak should be gone.

[Charlie Reis, 2013-12-17 23:06:39]

Just fixed two merge conflicts with John's http://crrev.com/241306.

[nasko, 2013-12-17 23:19:36]

LGTM

[Charlie Reis, 2013-12-18 00:07:46]

Committed patchset #2 manually as r241423 (presubmit successful).