Revert 284322 "Allow EmbedRoot to be called multiple times."

Revert 284322 "Allow EmbedRoot to be called multiple times."

> Allow EmbedRoot to be called multiple times.
> 
> Subsequent calls to EmbedRoot are now delegated to the window manager. This allows an application that was not created via the embed flow to obtain a connection to the view manager by asking the view manager init service to embed it somewhere. The init service just forwards this to the window manager. This is effectively like asking the window manager to create a toplevel window.
> 
> R=sky@chromium.org
> BUG=none
> 
> Review URL: https://codereview.chromium.org/403083002

TBR=ben@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=284323

[Ben Goodger (Google), 2014-07-19 06:19:56]

Committed patchset #1 manually as r284323 (tree was closed).