Neuter the wrong-way ServiceProvider (a.k.a. exposed_services).

You can still give it to ConnectToApplication(), but mojo_shell will
drop it on the floor.

R=vardhan@google.com
BUG=#762

Review URL: https://codereview.chromium.org/1965563002 .
diff --git a/shell/application_manager/shell_impl.cc b/shell/application_manager/shell_impl.cc
index b1c97c1..bdd38f1 100644
--- a/shell/application_manager/shell_impl.cc
+++ b/shell/application_manager/shell_impl.cc
@@ -69,14 +69,12 @@
                            identity_.url.spec());
 }
 
-void ShellImpl::ConnectToClient(
-    const GURL& requested_url,
-    const GURL& requestor_url,
-    InterfaceRequest<ServiceProvider> services,
-    InterfaceHandle<ServiceProvider> exposed_services) {
-  application_->AcceptConnection(
-      String::From(requestor_url), std::move(services),
-      std::move(exposed_services), requested_url.spec());
+void ShellImpl::ConnectToClient(const GURL& requested_url,
+                                const GURL& requestor_url,
+                                InterfaceRequest<ServiceProvider> services) {
+  application_->AcceptConnection(String::From(requestor_url),
+                                 std::move(services), nullptr,
+                                 requested_url.spec());
 }
 
 void ShellImpl::ConnectToApplication(
@@ -88,8 +86,9 @@
     LOG(ERROR) << "Error: invalid URL: " << app_url;
     return;
   }
+  LOG_IF(ERROR, exposed_services) << "exposed_services no longer supported!";
   manager_->ConnectToApplication(app_gurl, identity_.url, std::move(services),
-                                 std::move(exposed_services), base::Closure());
+                                 base::Closure());
 }
 
 void ShellImpl::CreateApplicationConnector(