Presentation API: allow the Mojo service to reject a getAvailability() call.

content/browser/presentation/presentation_service_impl_unittest.cc

Index: content/browser/presentation/presentation_service_impl_unittest.cc
diff --git a/content/browser/presentation/presentation_service_impl_unittest.cc b/content/browser/presentation/presentation_service_impl_unittest.cc
index dc3e5b2d99c7d5385c79ebfdd0f1f1610bb1f4f5..74f968dccc0d32af114e1ef0595fa4d03c794139 100644
--- a/content/browser/presentation/presentation_service_impl_unittest.cc
+++ b/content/browser/presentation/presentation_service_impl_unittest.cc
@@ -139,6 +139,9 @@ class MockPresentationServiceClient :
       presentation::PresentationSessionState new_state) override {
     NOTIMPLEMENTED();
   }
+  void OnScreenAvailabilityNotSupported() override {
+    NOTIMPLEMENTED();
+  }
 };
 
 class PresentationServiceImplTest : public RenderViewHostImplTestHarness {