[sensors] Close mock sensor stubs after test is finished

third_party/WebKit/Source/modules/sensor/SensorProxy.h

Index: third_party/WebKit/Source/modules/sensor/SensorProxy.h
diff --git a/third_party/WebKit/Source/modules/sensor/SensorProxy.h b/third_party/WebKit/Source/modules/sensor/SensorProxy.h
index 05c7c446b6f7d8a58ec576cd661ee3a616593ddb..942b0d7bad0a78bba1934509b17548160c6eb6cc 100644
--- a/third_party/WebKit/Source/modules/sensor/SensorProxy.h
+++ b/third_party/WebKit/Source/modules/sensor/SensorProxy.h
@@ -81,9 +81,10 @@ class SensorProxy final : public GarbageCollectedFinalized<SensorProxy>,
   void SensorReadingChanged() override;
 
   // Generic handler for a fatal error.
+  // String parameters are intentionally copied.
   void handleSensorError(ExceptionCode = UnknownError,
-                         const String& sanitizedMessage = String(),
-                         const String& unsanitizedMessage = String());
+                         String sanitizedMessage = String(),
+                         String unsanitizedMessage = String());
 
   void onSensorCreated(device::mojom::blink::SensorInitParamsPtr,
                        device::mojom::blink::SensorClientRequest);