Refactor resolution code in the vm to properly handle ambiguity errors.

runtime/vm/parser_test.cc

Index: runtime/vm/parser_test.cc
===================================================================
--- runtime/vm/parser_test.cc	(revision 25114)
+++ runtime/vm/parser_test.cc	(working copy)
@@ -16,7 +16,7 @@
 
 void DumpFunction(const Library& lib, const char* cname, const char* fname) {
   const String& classname = String::Handle(Symbols::New(cname));
-  Class& cls = Class::Handle(lib.LookupClass(classname));
+  Class& cls = Class::Handle(lib.LookupClass(classname, NULL));
   EXPECT(!cls.IsNull());
 
   String& funcname = String::Handle(String::New(fname));
@@ -50,7 +50,7 @@
                 bool expect_static,
                 bool is_final) {
   const String& classname = String::Handle(Symbols::New(class_name));
-  Class& cls = Class::Handle(lib.LookupClass(classname));
+  Class& cls = Class::Handle(lib.LookupClass(classname, NULL));
   EXPECT(!cls.IsNull());
 
   String& fieldname = String::Handle(String::New(field_name));
@@ -85,7 +85,7 @@
                    const char* function_name,
                    bool expect_static) {
   const String& classname = String::Handle(Symbols::New(class_name));
-  Class& cls = Class::Handle(lib.LookupClass(classname));
+  Class& cls = Class::Handle(lib.LookupClass(classname, NULL));
   EXPECT(!cls.IsNull());
 
   String& functionname = String::Handle(String::New(function_name));