dbus: Suppress NameHasNoOwner errors when connecting to signals

dbus/object_proxy.cc

 // 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.
 
 #include "dbus/bus.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
@@ skipping 594 matching lines @@
                << error.name() << ": " << error.message();
     return false;
   }
   // Store the match rule, so that we can remove this in Detach().
   match_rules_.insert(match_rule);
   return true;
 }
 
 void ObjectProxy::UpdateNameOwnerAndBlock() {
   bus_->AssertOnDBusThread();
+  // Errors should be suppressed here, as the service may not be yet running
+  // when connecting to signals of the service, which is just fine.
+  // The ObjectProxy will be notified when the service is launched via
+  // NameOwnerChanged signal. See also comments in ConnectToSignalInternal().
   service_name_owner_ =
-      bus_->GetServiceOwnerAndBlock(service_name_, Bus::REPORT_ERRORS);
+      bus_->GetServiceOwnerAndBlock(service_name_, Bus::SUPPRESS_ERRORS);
 }
 
 DBusHandlerResult ObjectProxy::HandleNameOwnerChanged(
     scoped_ptr<Signal> signal) {
   DCHECK(signal);
   bus_->AssertOnDBusThread();
 
   // Confirm the validity of the NameOwnerChanged signal.
   if (signal->GetMember() == kNameOwnerChangedMember &&
       signal->GetInterface() == kDBusSystemObjectInterface &&
@@ skipping 19 matching lines @@
       }
     }
   }
 
   // Always return unhandled to let other object proxies handle the same
   // signal.
   return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 }
 
 }  // namespace dbus