Revert of Move WebUI ownership from the RenderFrameHostManager to the RenderFrameHost.

Revert of Move WebUI ownership from the RenderFrameHostManager to the RenderFrameHost. (patchset #37 id:900001 of https://codereview.chromium.org/1352813006/ )

Reason for revert:
Due to crashes in RenderFrameHostManager::CheckWebUITransition.

Original issue's description:
> Move WebUI ownership from the RenderFrameHostManager to the RenderFrameHost.
>
> This change refactors the current ownership of the WebUI instance,
> moving it from the RenderFrameHostManager to the RenderFrameHost which
> is directly associated with the WebUI.
>
> The design document for this change is here:
> https://docs.google.com/a/chromium.org/document/d/1jrge5ulZ1YtqSR3WkNXzrtxhd3JXcWm8_zWBhEjaJtI
>
> BUG=508850
>
> Committed: https://crrev.com/e5c678bf5b084988a60a4636342414f2831c1695
> Cr-Commit-Position: refs/heads/master@{#358050}

TBR=clamy@chromium.org,nasko@chromium.org,creis@chromium.org,dbeam@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=508850
Committed: https://crrev.com/795f1b299c6f5900c12495f972a0c62d2c963419
Cr-Commit-Position: refs/heads/master@{#358297}

[carlosk, 2015-11-06 10:33:07]

Created Revert of Move WebUI ownership from the RenderFrameHostManager to the
RenderFrameHost.

[commit-bot: I haz the power, 2015-11-06 10:33:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1422043007/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1422043007/1

[commit-bot: I haz the power, 2015-11-06 10:34:21]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-06 10:35:04]

Patchset 1 (id:??) landed as
https://crrev.com/795f1b299c6f5900c12495f972a0c62d2c963419
Cr-Commit-Position: refs/heads/master@{#358297}