Change resolving of instance methods to check early for name mismatch.

runtime/vm/object.h

Index: runtime/vm/object.h
===================================================================
--- runtime/vm/object.h	(revision 25039)
+++ runtime/vm/object.h	(working copy)
@@ -27,6 +27,7 @@
 CLASS_LIST(DEFINE_FORWARD_DECLARATION)
 #undef DEFINE_FORWARD_DECLARATION
 class Api;
+class ArgumentsDescriptor;
 class Assembler;
 class Closure;
 class Code;
@@ -1636,16 +1637,18 @@
 
   // Returns true if the argument counts are valid for calling this function.
   // Otherwise, it returns false and the reason (if error_message is not NULL).
-  bool AreValidArgumentCounts(int num_arguments,
-                              int num_named_arguments,
+  bool AreValidArgumentCounts(intptr_t num_arguments,
+                              intptr_t num_named_arguments,
                               String* error_message) const;
 
   // Returns true if the total argument count and the names of optional
   // arguments are valid for calling this function.
   // Otherwise, it returns false and the reason (if error_message is not NULL).
-  bool AreValidArguments(int num_arguments,
+  bool AreValidArguments(intptr_t num_arguments,
                          const Array& argument_names,
                          String* error_message) const;
+  bool AreValidArguments(const ArgumentsDescriptor& args_desc,
+                         String* error_message) const;
 
   // Fully qualified name uniquely identifying the function under gdb and during
   // ast printing. The special ':' character, if present, is replaced by '_'.