Remove obsolete global SubString method.

src/handles.h

 // Copyright 2011 the V8 project authors. 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.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 281 matching lines @@
 Handle<JSArray> GetKeysFor(Handle<JSReceiver> object, bool* threw);
 Handle<FixedArray> ReduceFixedArrayTo(Handle<FixedArray> array, int length);
 Handle<FixedArray> GetEnumPropertyKeys(Handle<JSObject> object,
                                        bool cache_result);
 
 // Computes the union of keys and return the result.
 // Used for implementing "for (n in object) { }"
 Handle<FixedArray> UnionOfKeys(Handle<FixedArray> first,
                                Handle<FixedArray> second);
 
-Handle<String> SubString(Handle<String> str,
-                         int start,
-                         int end,
-                         PretenureFlag pretenure = NOT_TENURED);
-
 // Sets the expected number of properties for the function's instances.
 void SetExpectedNofProperties(Handle<JSFunction> func, int nof);
 
 // Sets the expected number of properties based on estimate from compiler.
 void SetExpectedNofPropertiesFromEstimate(Handle<SharedFunctionInfo> shared,
                                           int estimate);
 
 
 Handle<JSGlobalProxy> ReinitializeJSGlobalProxy(
     Handle<JSFunction> constructor,
@@ skipping 23 matching lines @@
  private:
   Isolate* isolate_;
   Object** limit_;
   int level_;
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HANDLES_H_