Delay Class parsing until the class is actually used.

runtime/vm/parser.h

Index: runtime/vm/parser.h
===================================================================
--- runtime/vm/parser.h	(revision 23087)
+++ runtime/vm/parser.h	(working copy)
@@ -143,14 +143,14 @@
 
 class Parser : public ValueObject {
  public:
-  Parser(const Script& script, const Library& library);
-  Parser(const Script& script, ParsedFunction* function, intptr_t token_pos);
-
   // Parse the top level of a whole script file and register declared classes
   // in the given library.
   static void ParseCompilationUnit(const Library& library,
                                    const Script& script);
 
+  // Parse top level of a class and register all functions/fields.
+  static void ParseClass(const Class& cls);
+
   static void ParseFunction(ParsedFunction* parsed_function);
 
   // Format and print a message with source location.
@@ -185,6 +185,9 @@
   struct Block;
   class TryBlocks;
 
+  Parser(const Script& script, const Library& library, intptr_t token_pos);
+  Parser(const Script& script, ParsedFunction* function, intptr_t token_pos);
+
   // The function for which we will generate code.
   const Function& current_function() const;
 
@@ -332,7 +335,8 @@
 
   // Support for parsing of scripts.
   void ParseTopLevel();
-  void ParseClassDefinition(const GrowableObjectArray& pending_classes);
+  void ParseClassDeclaration(const GrowableObjectArray& pending_classes);
+  void ParseClassDefinition(const Class& cls);
   void ParseMixinTypedef(const GrowableObjectArray& pending_classes);
   void ParseTypedef(const GrowableObjectArray& pending_classes);
   void ParseTopLevelVariable(TopLevel* top_level);