Add data-URI support class to dart:core (next to Uri).

runtime/vm/benchmark_test.cc

Index: runtime/vm/benchmark_test.cc
diff --git a/runtime/vm/benchmark_test.cc b/runtime/vm/benchmark_test.cc
index 1b22bc521a4498b9fa257b00c05b1f95d1b3c13a..171fbdac4f54b4c792c667cea214b0a0f0a62671 100644
--- a/runtime/vm/benchmark_test.cc
+++ b/runtime/vm/benchmark_test.cc
@@ -280,10 +280,10 @@ static void func(Dart_NativeArguments args) {
 static Dart_Handle PreparePackageRoot(const char* package_root,
                                       Dart_Handle builtin_lib) {
   // First ensure all required libraries are available.
-  Dart_Handle url = NewString(bin::DartUtils::kCoreLibURL);
+  Dart_Handle url = NewString(bin::DartUtils::kUriLibURL);
   DART_CHECK_VALID(url);
-  Dart_Handle core_lib = Dart_LookupLibrary(url);
-  DART_CHECK_VALID(core_lib);
+  Dart_Handle uri_lib = Dart_LookupLibrary(url);
+  DART_CHECK_VALID(uri_lib);
   url = NewString(bin::DartUtils::kAsyncLibURL);
   DART_CHECK_VALID(url);
   Dart_Handle async_lib = Dart_LookupLibrary(url);
@@ -331,7 +331,7 @@ static Dart_Handle PreparePackageRoot(const char* package_root,
   DART_CHECK_VALID(result);
 
   bin::DartUtils::PrepareAsyncLibrary(async_lib, isolate_lib);
-  bin::DartUtils::PrepareCoreLibrary(core_lib, builtin_lib, false);
+  bin::DartUtils::PrepareUriLibrary(uri_lib, builtin_lib, false);
   bin::DartUtils::PrepareIsolateLibrary(isolate_lib);
   bin::DartUtils::PrepareIOLibrary(io_lib);
   return Dart_True();