Revert of Make RenderFrame(Host) own a RenderWidget(Host).

Revert of Make RenderFrame(Host) own a RenderWidget(Host). (patchset #21 id:400001 of https://codereview.chromium.org/616133002/)

Reason for revert:
Broke Blink Mac dbg compile:

http://build.chromium.org/p/chromium.webkit/builders/Mac%20Builder%20%28dbg%29/builds/72778/steps/compile/logs/stdio

This error seems somewhat odd; the patch looks correct to me, so I'm not sure why the linker is giving missing symbol errors.

Original issue's description:
> Make RenderFrame(Host) own a RenderWidget(Host).
> 
> When a RenderFrameHost is created for an out-of-process iframe, it
> will create a RenderWidgetHost to manage rendering and input events for
> the iframe and its same-process frame descendants. A corresponding
> RenderWidget is created in the renderer process.
> 
> BUG=419087
> 
> Committed: https://crrev.com/2dfb76d84f4ebde602c1c3cde700dcf71b4d1bd6
> Cr-Commit-Position: refs/heads/master@{#312451}
> 
> Committed: https://crrev.com/a719983b5525a477724350ee9eba20e574d0eb3b
> Cr-Commit-Position: refs/heads/master@{#312702}

TBR=creis@chromium.org,nasko@chromium.org,nick@chromium.org,dmazzoni@chromium.org,kenrb@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=419087

[Peter Kasting, 2015-01-23 00:26:48]

Created Revert of Make RenderFrame(Host) own a RenderWidget(Host).

[commit-bot: I haz the power, 2015-01-23 00:28:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/867843002/1

[dcheng, 2015-01-23 00:30:16]

The CQ bit was unchecked by dcheng@chromium.org

[commit-bot: I haz the power, 2015-01-23 00:30:18]

The CQ bit was unchecked by commit-bot@chromium.org

[dcheng, 2015-01-23 00:30:27]

dcheng@chromium.org changed reviewers:
+ dcheng@chromium.org

[dcheng, 2015-01-23 00:30:27]

The followup builds look fine:
http://build.chromium.org/p/chromium.webkit/builders/Mac%20Builder%20%28dbg%29/

Does this really need to be reverted?

[dcheng, 2015-01-23 00:32:21]

Here's a previous time I had an issue with the Mac builders failing for no good
reason on a change:
https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/mwOVXeGxH2A

I ended up relanding the patch as is, and the tree was fine. So I think this
might just be one of those random failures.

[Peter Kasting, 2015-01-23 00:39:06]

Closing.