Remove check for scheme in source-loader.

pkg/front_end/lib/src/fasta/fasta_codes_generated.dart

 // Copyright (c) 2017, 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.
 
 // NOTE: THIS FILE IS GENERATED. DO NOT EDIT.
 //
 // Instead modify 'pkg/front_end/messages.yaml' and run
 // 'pkg/front_end/tool/_fasta/generate_messages.dart' to update.
 
 part of fasta.codes;
@@ skipping 1653 matching lines @@
 );
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 Message _withArgumentsInternalProblemUnsupported(String name) {
   return new Message(codeInternalProblemUnsupported,
       message: """Unsupported operation: '$name'.""",
       arguments: {'name': name});
 }
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<Message Function(Uri uri_)>
+    templateInternalProblemUriMissingScheme =
+    const Template<Message Function(Uri uri_)>(
+        messageTemplate: r"""The URI '#uri' has no scheme.""",
+        withArguments: _withArgumentsInternalProblemUriMissingScheme);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(Uri uri_)> codeInternalProblemUriMissingScheme =
+    const Code<Message Function(Uri uri_)>(
+  "InternalProblemUriMissingScheme",
+  templateInternalProblemUriMissingScheme,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInternalProblemUriMissingScheme(Uri uri_) {
+  String uri = relativizeUri(uri_);
+  return new Message(codeInternalProblemUriMissingScheme,
+      message: """The URI '$uri' has no scheme.""", arguments: {'uri': uri_});
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Template<Message Function(String string)>
     templateInternalVerificationError =
     const Template<Message Function(String string)>(
         messageTemplate:
             r"""Verification of the generated program failed: #string.""",
         withArguments: _withArgumentsInternalVerificationError);
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Code<Message Function(String string)> codeInternalVerificationError =
     const Code<Message Function(String string)>(
@@ skipping 1414 matching lines @@
         r"""'yield' can't be used as an identifier in 'async', 'async*', or 'sync*' methods.""");
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Code<Null> codeYieldNotGenerator = messageYieldNotGenerator;
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const MessageCode messageYieldNotGenerator = const MessageCode(
     "YieldNotGenerator",
     dart2jsCode: "*ignored*",
     message: r"""'yield' can only be used in 'sync*' or 'async*' methods.""");