Do not spawn a thread in browser/interactive ui tests before spawning sandbox host process

chromeos/dbus/dbus_thread_manager.h

 // Copyright (c) 2012 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 CHROMEOS_DBUS_DBUS_THREAD_MANAGER_H_
 #define CHROMEOS_DBUS_DBUS_THREAD_MANAGER_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 65 matching lines @@
 // WeakPtrFactory when creating callbacks that run on UI thread. See
 // session_manager_client.cc for examples.
 //
 class CHROMEOS_EXPORT DBusThreadManager {
  public:
   // Sets the global instance. Must be called before any calls to Get().
   // We explicitly initialize and shut down the global object, rather than
   // making it a Singleton, to ensure clean startup and shutdown.
   static void Initialize();
 
-  // Similar to Initialize(), but can inject an alternative
-  // DBusThreadManager such as MockDBusThreadManager for testing.
-  // The injected object will be owned by the internal pointer and deleted
-  // by Shutdown().
+  // Sets an alternative DBusThreadManager such as MockDBusThreadManager
+  // to be used in |Initialize()| for testing. Tests that call
+  // DBusThreadManager::Initialize() (such as browser_tests and
+  // interactive_ui_tests) should use this instead of calling
+  // |InitiailzeForTesting|.  The injected object will be owned by the
+  // internal pointer and deleted by Shutdown().
+  static void SetInstanceForTesting(DBusThreadManager* dbus_thread_manager);
+
+  // Similar to Initialize(), but injects an alternative
+  // DBusThreadManager using SetInstanceForTest first.  The injected
+  // object will be owned by the internal pointer and deleted by
+  // Shutdown().
   static void InitializeForTesting(DBusThreadManager* dbus_thread_manager);
 
   // Initialize with stub implementations for tests based on stubs.
   static void InitializeWithStub();
 
   // Returns true if DBusThreadManager has been initialized. Call this to
   // avoid initializing + shutting down DBusThreadManager more than once.
   static bool IsInitialized();
 
   // Destroys the global instance.
@@ skipping 55 matching lines @@
 
   // Initializes |client| with the |system_bus_|.
   static void InitClient(DBusClient* client);
 
   DISALLOW_COPY_AND_ASSIGN(DBusThreadManager);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_DBUS_THREAD_MANAGER_H_