Add media remoting unittests to media_unittests.

media/BUILD.gn

Index: media/BUILD.gn
diff --git a/media/BUILD.gn b/media/BUILD.gn
index e25c10a8c191d0aeb649c64f41025c2d686d367e..560c000d483bcf36792b7b7b7c959f94fa1da6ef 100644
--- a/media/BUILD.gn
+++ b/media/BUILD.gn
@@ -727,6 +727,10 @@ test("media_unittests") {
       "//ui/android:ui_java",
     ]
   }
+
+  if (enable_media_remoting) {
+    deps += [ "//media/remoting:media_remoting_tests" ]
+  }
 }
 
 test("media_perftests") {