Make patching of classes lazy.

lib/compiler/implementation/scanner/class_element_parser.dart

 // Copyright (c) 2011, 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.
 
 class ClassElementParser extends PartialParser {
   ClassElementParser(Listener listener) : super(listener);
 
   Token parseClassBody(Token token) => fullParseClassBody(token);
 }
 
 class PartialClassElement extends ClassElement {
   final Token beginToken;
   final Token endToken;
   Node cachedNode;
 
   PartialClassElement(SourceString name,
                       Token this.beginToken,
                       Token this.endToken,
                       Element enclosing,
                       int id)
       : super(name, enclosing, id);
 
   ClassNode parseNode(DiagnosticListener diagnosticListener) {
     if (cachedNode != null) return cachedNode;
+    // TODO(ahe): Measure these tasks.
     MemberListener listener = new MemberListener(diagnosticListener, this);
     Parser parser = new ClassElementParser(listener);
     Token token = parser.parseTopLevelDeclaration(beginToken);
     assert(token === endToken.next);
     cachedNode = listener.popNode();
     assert(listener.nodes.isEmpty());
+    if (isPatched) {
+      // TODO(lrn): Perhaps extract functionality so it doesn't need compiler.
+      Compiler compiler = diagnosticListener;
+      ClassNode patchNode = compiler.patchParser.parsePatchClassNode(patch);
+      Link<Element> patches = patch.localMembers;
+      compiler.applyContainerPatch(this, patches);
+    }
     return cachedNode;
   }
 
   Token position() => beginToken;
 
   bool isInterface() => beginToken.stringValue === "interface";
 
   PartialClassElement cloneTo(Element enclosing, DiagnosticListener listener) {
     parseNode(listener);
     // TODO(lrn): Is copying id acceptable?
@@ skipping 118 matching lines @@
   }
 
   void endInitializers(int count, Token beginToken, Token endToken) {
     pushNode(null);
   }
 
   void addMember(Element memberElement) {
     enclosingElement.addMember(memberElement, listener);
   }
 }