Add support for IncrementCounter in Hydrogen.

src/assembler.cc

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 1060 matching lines @@
 ExternalReference ExternalReference::date_cache_stamp(Isolate* isolate) {
   return ExternalReference(isolate->date_cache()->stamp_address());
 }
 
 
 ExternalReference ExternalReference::stress_deopt_count(Isolate* isolate) {
   return ExternalReference(isolate->stress_deopt_count_address());
 }
 
 
+ExternalReference ExternalReference::null() {
+  return ExternalReference(reinterpret_cast<Address>(0));
+}
+
+
 ExternalReference ExternalReference::transcendental_cache_array_address(
     Isolate* isolate) {
   return ExternalReference(
       isolate->transcendental_cache()->cache_array_address());
 }
 
 
 ExternalReference ExternalReference::new_deoptimizer_function(
     Isolate* isolate) {
   return ExternalReference(
@@ skipping 586 matching lines @@
     assembler_->RecordRelocInfo(RelocInfo::POSITION, state_.current_position);
     state_.written_position = state_.current_position;
     written = true;
   }
 
   // Return whether something was written.
   return written;
 }
 
 } }  // namespace v8::internal