Add a few missing overrides found by a new clang warning.

src/ic/ic.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_IC_H_
 #define V8_IC_H_
 
 #include "src/ic/ic-state.h"
 #include "src/macro-assembler.h"
 
@@ skipping 398 matching lines @@
   }
 
   virtual Handle<Code> megamorphic_stub() OVERRIDE;
 
   // Update the inline cache and the global stub cache based on the
   // lookup result.
   void UpdateCaches(LookupIterator* lookup);
 
   virtual Handle<Code> CompileHandler(LookupIterator* lookup,
                                       Handle<Object> unused,
-                                      CacheHolderFlag cache_holder);
+                                      CacheHolderFlag cache_holder) OVERRIDE;
 
  private:
   virtual Handle<Code> pre_monomorphic_stub() const;
   static Handle<Code> pre_monomorphic_stub(Isolate* isolate,
                                            ExtraICState extra_state);
 
   Handle<Code> SimpleFieldLoad(FieldIndex index);
 
   static void Clear(Isolate* isolate, Address address, Code* target,
                     ConstantPoolArray* constant_pool);
@@ skipping 108 matching lines @@
 
   static Handle<Code> pre_monomorphic_stub(Isolate* isolate,
                                            StrictMode strict_mode);
 
   // Update the inline cache and the global stub cache based on the
   // lookup result.
   void UpdateCaches(LookupIterator* lookup, Handle<Object> value,
                     JSReceiver::StoreFromKeyed store_mode);
   virtual Handle<Code> CompileHandler(LookupIterator* lookup,
                                       Handle<Object> value,
-                                      CacheHolderFlag cache_holder);
+                                      CacheHolderFlag cache_holder) OVERRIDE;
 
  private:
   inline void set_target(Code* code);
 
   static void Clear(Isolate* isolate, Address address, Code* target,
                     ConstantPoolArray* constant_pool);
 
   friend class IC;
 };
 
@@ skipping 173 matching lines @@
 
 // Support functions for interceptor handlers.
 DECLARE_RUNTIME_FUNCTION(LoadPropertyWithInterceptorOnly);
 DECLARE_RUNTIME_FUNCTION(LoadPropertyWithInterceptor);
 DECLARE_RUNTIME_FUNCTION(LoadElementWithInterceptor);
 DECLARE_RUNTIME_FUNCTION(StorePropertyWithInterceptor);
 }
 }  // namespace v8::internal
 
 #endif  // V8_IC_H_