Add dart:web to VM.

runtime/bin/main.cc

 // 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.
 
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 
 #include "include/dart_api.h"
 #include "include/dart_debugger_api.h"
@@ skipping 389 matching lines @@
     if (DartUtils::IsDartCryptoLibURL(url_string)) {
       id = Builtin::kCryptoLibrary;
     } else if (DartUtils::IsDartIOLibURL(url_string)) {
       id = Builtin::kIOLibrary;
     } else if (DartUtils::IsDartJsonLibURL(url_string)) {
       id = Builtin::kJsonLibrary;
     } else if (DartUtils::IsDartUriLibURL(url_string)) {
       id = Builtin::kUriLibrary;
     } else if (DartUtils::IsDartUtfLibURL(url_string)) {
       id = Builtin::kUtfLibrary;
+    } else if (DartUtils::IsDartWebLibURL(url_string)) {
+      id = Builtin::kWebLibrary;
     } else {
       return Dart_Error("Do not know how to load '%s'", url_string);
     }
     return Builtin::LoadLibrary(id);
   } else {
     // Get the file path out of the url.
     Dart_Handle builtin_lib = Builtin::LoadLibrary(Builtin::kBuiltinLibrary);
     Dart_Handle file_path = FilePathFromUri(url, builtin_lib);
     if (Dart_IsError(file_path)) {
       return file_path;
@@ skipping 384 matching lines @@
   DumpPprofSymbolInfo();
   // Shutdown the isolate.
   Dart_ShutdownIsolate();
   // Terminate process exit-code handler.
   Process::TerminateExitCodeHandler();
 
   free(const_cast<char*>(original_working_directory));
 
   return 0;
 }