Allow patch files to add top-level declarations to the patched library.

lib/compiler/implementation/scanner/listener.dart

 // 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.
 
 final bool VERBOSE = false;
 
 /**
  * A parser event listener that does nothing except throw exceptions
  * on parser errors.
  */
@@ skipping 1496 matching lines @@
       }
     }
     cachedNode = parse(listener, getCompilationUnit(), parseFunction);
     return cachedNode;
   }
 
   Token position() {
     if (patch !== null) return patch.position();
     return findMyName(beginToken);
   }
+
+  PartialFunctionElement cloneTo(Element enclosing,
+                                 DiagnosticListener listener) {
+    if (patch !== null) {
+      listener.cancel("Cloning a patched function.", element: this);
+    }
+    PartialFunctionElement result = new PartialFunctionElement(
+        name, beginToken, getOrSet, endToken, kind, modifiers, enclosing);
+    result.scriptOverride = getScript();
+    return result;
+  }
 }
 
 class PartialFieldListElement extends VariableListElement {
   final Token beginToken;
   final Token endToken;
 
   PartialFieldListElement(Token this.beginToken,
                           Token this.endToken,
                           Modifiers modifiers,
                           Element enclosing)
     : super(ElementKind.VARIABLE_LIST, modifiers, enclosing);
 
   VariableDefinitions parseNode(DiagnosticListener listener) {
     if (cachedNode != null) return cachedNode;
     cachedNode = parse(listener,
                        getCompilationUnit(),
                        (p) => p.parseVariablesDeclaration(beginToken));
     if (!cachedNode.modifiers.isVar() &&
         !cachedNode.modifiers.isFinal() &&
         !cachedNode.modifiers.isConst() &&
         cachedNode.type === null) {
       listener.cancel('A field declaration must start with var, final, '
                       'const, or a type annotation.',
                       cachedNode);
     }
     return cachedNode;
   }
 
   Token position() => beginToken; // findMyName doesn't work. I'm nameless.
+
+  PartialFieldListElement cloneTo(Element enclosing,
+                                  DiagnosticListener listener) {
+    PartialFieldListElement result = new PartialFieldListElement(
+        beginToken, endToken, modifiers, enclosing);
+    result.scriptOverride = getScript();
+    return result;
+  }
 }
 
 class PartialTypedefElement extends TypedefElement {
   final Token token;
 
   PartialTypedefElement(SourceString name, Element enclosing, this.token)
       : super(name, enclosing);
 
   Node parseNode(DiagnosticListener listener) {
     if (cachedNode !== null) return cachedNode;
     cachedNode = parse(listener,
                        getCompilationUnit(),
                        (p) => p.parseTopLevelDeclaration(token));
     return cachedNode;
   }
 
   position() => findMyName(token);
+
+  PartialTypedefElement cloneTo(Element enclosing,
+                                DiagnosticListener listener) {
+    PartialTypedefElement result =
+        new PartialTypedefElement(name, enclosing, token);
+    result.scriptOverride = getScript();
+    return result;
+  }
 }
 
 Node parse(DiagnosticListener diagnosticListener,
            CompilationUnitElement element,
            doParse(Parser parser)) {
   NodeListener listener = new NodeListener(diagnosticListener, element);
   doParse(new Parser(listener));
   Node node = listener.popNode();
   assert(listener.nodes.isEmpty());
   return node;
 }