Revert of Don't ensure, in single-process mode, that WebUI render views are the only ones in the process, as …

content/browser/frame_host/render_frame_host_manager.cc

Index: content/browser/frame_host/render_frame_host_manager.cc
diff --git a/content/browser/frame_host/render_frame_host_manager.cc b/content/browser/frame_host/render_frame_host_manager.cc
index 9f9ea6fefcd6fd284885f5768542b19c1e09e17f..d3eb8db1c7863d31d5f4f27be9a841f30e6f1576 100644
--- a/content/browser/frame_host/render_frame_host_manager.cc
+++ b/content/browser/frame_host/render_frame_host_manager.cc
@@ -1254,9 +1254,8 @@
     render_view_host->AllowBindings(pending_web_ui()->GetBindings());
   } else {
     // Ensure that we don't create an unprivileged RenderView in a WebUI-enabled
-    // process unless it's swapped out or we run in single-process mode.
-    if (render_view_host->is_active()
-        && !RenderProcessHost::run_renderer_in_process()) {
+    // process unless it's swapped out.
+    if (render_view_host->is_active()) {
       CHECK(!ChildProcessSecurityPolicyImpl::GetInstance()->HasWebUIBindings(
                 render_view_host->GetProcess()->GetID()));
     }