Beginning support for library prefixes in the dart API.

runtime/vm/snapshot_test.cc

Index: runtime/vm/snapshot_test.cc
diff --git a/runtime/vm/snapshot_test.cc b/runtime/vm/snapshot_test.cc
index dd8285eca477fe0803efa98474ef4b46a0051183..f8e6009bfbd8a00128eb3d040e276b91dde2b488 100644
--- a/runtime/vm/snapshot_test.cc
+++ b/runtime/vm/snapshot_test.cc
@@ -1001,12 +1001,15 @@ UNIT_TEST_CASE(ScriptSnapshot) {
     // Load the library.
     Dart_Handle import_lib = Dart_LoadLibrary(Dart_NewString("dart:import-lib"),
                                               Dart_NewString(kLibScriptChars));
+    Dart_Handle prefix = Dart_NewString("");
     EXPECT_VALID(import_lib);
 
     // Create a test library and Load up a test script in it.
     TestCase::LoadTestScript(kScriptChars, NULL);
 
-    EXPECT_VALID(Dart_LibraryImportLibrary(TestCase::lib(), import_lib));
+    EXPECT_VALID(Dart_LibraryImportLibrary(TestCase::lib(),
+                                           import_lib,
+                                           prefix));
 
     // Get list of library URLs loaded and save the count.
     Dart_Handle libs = Dart_GetLibraryURLs();