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

runtime/include/dart_api.h

 /*
  * Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
  * for details. All rights reserved. Use of this source code is governed by a
  * BSD-style license that can be found in the LICENSE file.
  */
 
 #ifndef INCLUDE_DART_API_H_
 #define INCLUDE_DART_API_H_
 
 /** \mainpage Dart Embedding API Reference
@@ skipping 2666 matching lines @@
  *
  * \return If no error occurs, the handler is set for the isolate.
  *   Otherwise an error handle is returned.
  *
  * TODO(turnidge): Document.
  */
 DART_EXPORT Dart_Handle Dart_SetLibraryTagHandler(
     Dart_LibraryTagHandler handler);
 
 /**
+ * Canonicalizes a url with respect to some library.
+ *
+ * The url is resolved with respect to the library's url and some url
+ * normalizations are performed.
+ *
+ * This canonicalization function should be sufficient for most
+ * embedders to implement the Dart_kCanonicalizeUrl tag.
+ *
+ * \param library The library relative to which the url is being
+ *                resolved.
+ * \param url The url being resolved and canonicalized.  This
+ *            parameter is a string handle.
+ *
+ * \return If no error occurs, a String object is returned.  Otherwise
+ *   an error handle is returned.
+ */
+DART_EXPORT Dart_Handle Dart_DefaultCanonicalizeUrl(Dart_Handle library,
+                                                    Dart_Handle url);
+
+/**
  * Loads the root script for the current isolate. The script can be
  * embedded in another file, for example in an html file.
  *
  * TODO(turnidge): Document.
  *
- * \line_offset is the number of text lines before the
+ * \param line_offset is the number of text lines before the
  *   first line of the Dart script in the containing file.
  *
- * \col_offset is the number of characters before the first character
+ * \param col_offset is the number of characters before the first character
  *   in the first line of the Dart script.
  */
 DART_EXPORT Dart_Handle Dart_LoadScript(Dart_Handle url,
                                         Dart_Handle source,
                                         intptr_t line_offset,
                                         intptr_t col_offset);
 
 /**
  * Loads the root script for current isolate from a snapshot.
  *
@@ skipping 345 matching lines @@
 /**
  *  Returns whether the VM was initialized with a precompiled snapshot. Only
  *  valid after Dart_Initialize.
  *  DEPRECATED. This is currently used to disable Platform.executable and
  *  Platform.resolvedExecutable under precompilation to prevent process
  *  spawning tests from becoming fork-bombs.
  */
 DART_EXPORT bool Dart_IsRunningPrecompiledCode();
 
 #endif  /* INCLUDE_DART_API_H_ */  /* NOLINT */