Change Dart_DefaultCanonicalizeUrl to accept the library url string instead of a library, this is u…

runtime/vm/unit_test.cc

Index: runtime/vm/unit_test.cc
diff --git a/runtime/vm/unit_test.cc b/runtime/vm/unit_test.cc
index 2059b71074eba059a616c23a3519a6b8dc12527f..b0c773eab2c413044e11a8a51a158471dde8f644 100644
--- a/runtime/vm/unit_test.cc
+++ b/runtime/vm/unit_test.cc
@@ -140,7 +140,11 @@ static Dart_Handle LibraryTagHandler(Dart_LibraryTag tag,
                                      Dart_Handle library,
                                      Dart_Handle url) {
   if (tag == Dart_kCanonicalizeUrl) {
-    return Dart_DefaultCanonicalizeUrl(library, url);
+    Dart_Handle library_url = Dart_LibraryUrl(library);
+    if (Dart_IsError(library_url)) {
+      return library_url;
+    }
+    return Dart_DefaultCanonicalizeUrl(library_url, url);
   }
   if (tag == Dart_kScriptTag) {
     // Reload request.