Canonicalize uris in C++ instead of Dart for the standalone embedder.

runtime/bin/dartutils.cc

Index: runtime/bin/dartutils.cc
diff --git a/runtime/bin/dartutils.cc b/runtime/bin/dartutils.cc
index b7f418b7a7cab7c68bbed5b6373039ae6fb55c26..8be3b29a3ce8bfea25422945f16c5ff7c86f0542 100644
--- a/runtime/bin/dartutils.cc
+++ b/runtime/bin/dartutils.cc
@@ -367,18 +367,6 @@ Dart_Handle DartUtils::LibraryFilePath(Dart_Handle library_uri) {
 }
 
 
-Dart_Handle DartUtils::ResolveUri(Dart_Handle library_url, Dart_Handle url) {
-  const int kNumArgs = 2;
-  Dart_Handle dart_args[kNumArgs];
-  dart_args[0] = library_url;
-  dart_args[1] = url;
-  return Dart_Invoke(DartUtils::BuiltinLib(),
-                     NewString("_resolveUri"),
-                     kNumArgs,
-                     dart_args);
-}
-
-
 static Dart_Handle LoadDataAsync_Invoke(Dart_Handle tag,
                                         Dart_Handle url,
                                         Dart_Handle library_url) {
@@ -397,6 +385,9 @@ static Dart_Handle LoadDataAsync_Invoke(Dart_Handle tag,
 Dart_Handle DartUtils::LibraryTagHandler(Dart_LibraryTag tag,
                                          Dart_Handle library,
                                          Dart_Handle url) {
+  if (tag == Dart_kCanonicalizeUrl) {
+    return Dart_DefaultCanonicalizeUrl(library, url);
+  }
   if (!Dart_IsLibrary(library)) {
     return Dart_NewApiError("not a library");
   }
@@ -420,10 +411,7 @@ Dart_Handle DartUtils::LibraryTagHandler(Dart_LibraryTag tag,
 
   // Handle canonicalization, 'import' and 'part' of 'dart:' libraries.
   if (is_dart_scheme_url || is_dart_library) {
-    if (tag == Dart_kCanonicalizeUrl) {
-      // These will be handled internally.
-      return url;
-    } else if (tag == Dart_kImportTag) {
+    if (tag == Dart_kImportTag) {
       Builtin::BuiltinLibraryId id = Builtin::FindId(url_string);
       if (id == Builtin::kInvalidLibrary) {
         return NewError("The built-in library '%s' is not available"
@@ -452,11 +440,6 @@ Dart_Handle DartUtils::LibraryTagHandler(Dart_LibraryTag tag,
     UNREACHABLE();
   }
 
-  if (tag == Dart_kCanonicalizeUrl) {
-    // Resolve the url within the context of the library's URL.
-    return ResolveUri(library_url, url);
-  }
-
   if (DartUtils::IsDartExtensionSchemeURL(url_string)) {
     // Load a native code shared library to use in a native extension
     if (tag != Dart_kImportTag) {