Remove support for Root identity singletons and rely on the all_users bit to be set. + test

mojo/shell/shell.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_SHELL_SHELL_H_
 #define MOJO_SHELL_SHELL_H_
 
 #include <map>
 #include <vector>
 
@@ skipping 96 matching lines @@
 
   // Completes a connection between a source and target application as defined
   // by |params|, exchanging InterfaceProviders between them. If no existing
   // instance of the target application is running, one will be loaded.
   //
   // If |client| is not null, there must not be an instance of the target
   // application already running. The shell will create a new instance and use
   // |client| to control it.
   void Connect(scoped_ptr<ConnectParams> params, mojom::ShellClientPtr client);
 
-  // Returns a running instance matching |identity|.
+  // Returns a running instance matching |identity|. This might be an instance
+  // running as a different user if one is available that services all users.
   Instance* GetExistingInstance(const Identity& identity) const;
-  // Like GetExistingInstance, but if no instance for |identity.user_id()| is
-  // found, looks for kRootUserID too.
-  Instance* GetExistingOrRootInstance(const Identity& identity) const;
 
   void NotifyPIDAvailable(uint32_t id, base::ProcessId pid);
 
   // Attempt to complete the connection requested by |params| by connecting to
   // an existing instance. If there is an existing instance, |params| is taken,
   // and this function returns true.
   bool ConnectToExistingInstance(scoped_ptr<ConnectParams>* params);
 
   Instance* CreateInstance(const Identity& target,
                            const CapabilitySpec& spec);
@@ skipping 65 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(Shell);
 };
 
 mojom::Connector::ConnectCallback EmptyConnectCallback();
 
 }  // namespace shell
 }  // namespace mojo
 
 #endif  // MOJO_SHELL_SHELL_H_