Implement spawnUri from dart:isolate. This function allows us to

runtime/vm/parser.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 VM_PARSER_H_
 #define VM_PARSER_H_
 
 #include "include/dart_api.h"
 
 #include "vm/ast.h"
@@ skipping 247 matching lines @@
   void ParseClassDefinition(const GrowableObjectArray& pending_classes);
   void ParseInterfaceDefinition(const GrowableObjectArray& pending_classes);
   void ParseFunctionTypeAlias(const GrowableObjectArray& pending_classes);
   void ParseTopLevelVariable(TopLevel* top_level);
   void ParseTopLevelFunction(TopLevel* top_level);
   void ParseTopLevelAccessor(TopLevel* top_level);
 
   // Support for parsing libraries.
   Dart_Handle CallLibraryTagHandler(Dart_LibraryTag tag,
                                     intptr_t token_pos,
-                                    const String& url,
-                                    const Array& import_map);
+                                    const String& url);
   void ParseLibraryDefinition();
   void ParseLibraryName();
   void ParseLibraryImport();
   void ParseLibraryInclude();
   void ParseLibraryResource();
 
   void ResolveTypeFromClass(const Class& cls,
                             ClassFinalizer::FinalizationKind finalization,
                             AbstractType* type);
   RawAbstractType* ParseType(ClassFinalizer::FinalizationKind finalization);
@@ skipping 240 matching lines @@
 
   // Allocate temporary only once per function.
   LocalVariable* expression_temp_;
 
   DISALLOW_COPY_AND_ASSIGN(Parser);
 };
 
 }  // namespace dart
 
 #endif  // VM_PARSER_H_