Add support for IncrementCounter in Hydrogen.

src/assembler.h

 // 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 811 matching lines @@
 
   static ExternalReference math_exp_constants(int constant_index);
   static ExternalReference math_exp_log_table();
 
   static ExternalReference page_flags(Page* page);
 
   static ExternalReference ForDeoptEntry(Address entry);
 
   static ExternalReference cpu_features();
 
-  Address address() const {return reinterpret_cast<Address>(address_);}
+  Address address() const { return reinterpret_cast<Address>(address_); }
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
   // Function Debug::Break()
   static ExternalReference debug_break(Isolate* isolate);
 
   // Used to check if single stepping is enabled in generated code.
   static ExternalReference debug_step_in_fp_address(Isolate* isolate);
 #endif
 
 #ifndef V8_INTERPRETED_REGEXP
@@ skipping 18 matching lines @@
   static void set_redirector(Isolate* isolate,
                              ExternalReferenceRedirector* redirector) {
     // We can't stack them.
     ASSERT(isolate->external_reference_redirector() == NULL);
     isolate->set_external_reference_redirector(
         reinterpret_cast<ExternalReferenceRedirectorPointer*>(redirector));
   }
 
   static ExternalReference stress_deopt_count(Isolate* isolate);
 
+  static ExternalReference null();
+
+  bool operator==(const ExternalReference& other) const {
+    return address_ == other.address_;
+  }
+
+  bool operator!=(const ExternalReference& other) const {
+    return !(*this == other);
+  }
+
  private:
   explicit ExternalReference(void* address)
       : address_(address) {}
 
   static void* Redirect(Isolate* isolate,
                         void* address,
                         Type type = ExternalReference::BUILTIN_CALL) {
     ExternalReferenceRedirector* redirector =
         reinterpret_cast<ExternalReferenceRedirector*>(
             isolate->external_reference_redirector());
@@ skipping 183 matching lines @@
  public:
   NullCallWrapper() { }
   virtual ~NullCallWrapper() { }
   virtual void BeforeCall(int call_size) const { }
   virtual void AfterCall() const { }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ASSEMBLER_H_