Fix crash in ViewManager: fail gracefully when no ServiceProvider is

services/view_manager/view_manager_app.cc

Index: services/view_manager/view_manager_app.cc
diff --git a/services/view_manager/view_manager_app.cc b/services/view_manager/view_manager_app.cc
index ec55f589971d55d4bb3b4ae0c2f09476726bce59..715d1b8b7578b0028c8e26d7660ce792ee94ac40 100644
--- a/services/view_manager/view_manager_app.cc
+++ b/services/view_manager/view_manager_app.cc
@@ -45,6 +45,9 @@ bool ViewManagerApp::ConfigureIncomingConnection(
   connection->AddService<ViewManagerService>(this);
   connection->AddService<WindowManagerInternalClient>(this);
   connection->ConnectToService(&wm_internal_);
+  // If no ServiceProvider has been sent, refuse the connection.

[sky, 2015/03/06 18:25:28]

This doesn't make sense. It is expected that the first connection is the window
manager and further that we can get WindowManagerInternal from it.

+  if (!wm_internal_)
+    return false;
   wm_internal_.set_error_handler(this);
 
   scoped_ptr<DefaultDisplayManager> display_manager(new DefaultDisplayManager(