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

runtime/vm/dart_entry.cc

Index: runtime/vm/dart_entry.cc
===================================================================
--- runtime/vm/dart_entry.cc	(revision 25321)
+++ runtime/vm/dart_entry.cc	(working copy)
@@ -119,7 +119,8 @@
 
   Class& invocation_mirror_class = Class::Handle(
       core_lib.LookupClass(
-          String::Handle(core_lib.PrivateName(Symbols::InvocationMirror()))));
+          String::Handle(core_lib.PrivateName(Symbols::InvocationMirror())),
+          NULL));  // No ambiguity error expected.
   ASSERT(!invocation_mirror_class.IsNull());
   const String& function_name =
       String::Handle(core_lib.PrivateName(Symbols::AllocateInvocationMirror()));
@@ -355,7 +356,8 @@
                                             const String& class_name,
                                             const String& constructor_name,
                                             const Array& arguments) {
-  const Class& cls = Class::Handle(lib.LookupClassAllowPrivate(class_name));
+  const Class& cls = Class::Handle(
+      lib.LookupClassAllowPrivate(class_name, NULL));  // No ambiguity expected.
   ASSERT(!cls.IsNull());
   // For now, we only support a non-parameterized or raw type.
   const int kNumExtraArgs = 2;  // implicit rcvr and construction phase args.
@@ -444,7 +446,9 @@
                                        function_name,
                                        kNumArguments,
                                        Object::empty_array(),
-                                       Resolver::kIsQualified);
+                                       Resolver::kIsQualified,
+                                       NULL);  // No ambiguity error expected.
+    ASSERT(!function.IsNull());
     isolate->object_store()->set_lookup_receive_port_function(function);
   }
   const Array& args = Array::Handle(Array::New(kNumArguments));
@@ -475,7 +479,9 @@
                                        function_name,
                                        kNumArguments,
                                        Object::empty_array(),
-                                       Resolver::kIsQualified);
+                                       Resolver::kIsQualified,
+                                       NULL);  // No ambiguity error expected.
+    ASSERT(!function.IsNull());
     isolate->object_store()->set_handle_message_function(function);
   }
   const Array& args = Array::Handle(isolate, Array::New(kNumArguments));
@@ -509,7 +515,9 @@
                               function_name,
                               kNumArguments,
                               Object::empty_array(),
-                              Resolver::kIsQualified));
+                              Resolver::kIsQualified,
+                              NULL));  // No ambiguity error expected.
+  ASSERT(!function.IsNull());
   const Array& args = Array::Handle(Array::New(kNumArguments));
   args.SetAt(0, Integer::Handle(Integer::New(port_id)));
   return DartEntry::InvokeFunction(function, args);