Revert of Reland #1 of: Move WebUI ownership from the RenderFrameHostManager to the RenderFrameHost.

Revert of Reland #1 of: Move WebUI ownership from the RenderFrameHostManager to the RenderFrameHost. (patchset #12 id:260001 of https://codereview.chromium.org/1426403006/ )

Reason for revert:
ExtensionApiTest.Debugger browser_tests failed on Win7 Tests (dbg)(1) Build #43339 with

[3192:3164:1120/071447:FATAL:render_frame_host_manager.cc(2372)] Check failed: !render_frame_host_->pending_web_ui().

Which was introduced with this change.

Original issue's description:
> Reland #1 of: Move WebUI ownership from the RenderFrameHostManager to the RenderFrameHost.
> (Revert: https://codereview.chromium.org/1422043007/)
>
> 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, 552253
>
> Committed: https://crrev.com/113503ad7f6957c1eb2bb12215c8d5fae3303ef6
> Cr-Commit-Position: refs/heads/master@{#360807}

TBR=clamy@chromium.org,nasko@chromium.org,creis@chromium.org,dbeam@chromium.org,carlosk@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=508850, 552253
Committed: https://crrev.com/4b8f0132c24e2ba0890192c9e5117f1c05cdf54d
Cr-Commit-Position: refs/heads/master@{#360828}

[grt (UTC plus 2), 2015-11-20 16:01:53]

Created Revert of Reland #1 of: Move WebUI ownership from the
RenderFrameHostManager to the RenderFrameHost.

[commit-bot: I haz the power, 2015-11-20 16:03:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1454883006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1454883006/1

[commit-bot: I haz the power, 2015-11-20 16:04:16]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-20 16:05:26]

Patchset 1 (id:??) landed as
https://crrev.com/4b8f0132c24e2ba0890192c9e5117f1c05cdf54d
Cr-Commit-Position: refs/heads/master@{#360828}