Remove calls to deprecated MessageLoop methods in blimp.

blimp/client/core/contents/blimp_navigation_controller_impl_unittest.cc

Index: blimp/client/core/contents/blimp_navigation_controller_impl_unittest.cc
diff --git a/blimp/client/core/contents/blimp_navigation_controller_impl_unittest.cc b/blimp/client/core/contents/blimp_navigation_controller_impl_unittest.cc
index 8b179de39d279e2d217b042d8a1eaad0b1e1ce93..9ead75c799c5f41a5be18789e11aab0f6c698860 100644
--- a/blimp/client/core/contents/blimp_navigation_controller_impl_unittest.cc
+++ b/blimp/client/core/contents/blimp_navigation_controller_impl_unittest.cc
@@ -42,7 +42,7 @@ TEST(BlimpNavigationControllerImplTest, BackForwardNavigation) {
   EXPECT_CALL(delegate, OnNavigationStateChanged());
 
   navigation_controller.LoadURL(kExampleURL);
-  loop.RunUntilIdle();
+  base::RunLoop().RunUntilIdle();
   EXPECT_EQ(kExampleURL, navigation_controller.GetURL());
 
   EXPECT_CALL(feature, GoBack(_));