Fix SettingsTestCase.test[Metrics|Breakpad]Reporting on Official

ios/chrome/app/application_delegate/metrics_mediator.mm

Index: ios/chrome/app/application_delegate/metrics_mediator.mm
diff --git a/ios/chrome/app/application_delegate/metrics_mediator.mm b/ios/chrome/app/application_delegate/metrics_mediator.mm
index 3b5ecee6992f944fc32d8e0d68da4e658581db76..b56e2870b3016bead6420260227c349bc89e7615 100644
--- a/ios/chrome/app/application_delegate/metrics_mediator.mm
+++ b/ios/chrome/app/application_delegate/metrics_mediator.mm
@@ -348,6 +348,7 @@ using metrics_mediator::kAppEnteredBackgroundDateKey;
   // reporting preference.  If it's disabled, or the wifi-only preference is
   // not set, we don't care.  In fact, we should not even be getting this call.
   DCHECK([self isMetricsReportingEnabledWifiOnly]);
+  DCHECK(connectionTypeObserverBridge_);
   // |wwanEnabled| is true if a cellular connection such as EDGE or GPRS is
   // used. Otherwise, either there is no connection available, or another link
   // (such as WiFi) is used.