Realize IWYU pattern for handles.h header.

src/futex-emulation.h

 // Copyright 2015 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_FUTEX_EMULATION_H_
 #define V8_FUTEX_EMULATION_H_
 
 #include <stdint.h>
 
 #include "src/allocation.h"
@@ skipping 13 matching lines @@
 
 namespace v8 {
 
 namespace base {
 class TimeDelta;
 }  // base
 
 namespace internal {
 
 class Isolate;
+class JSArrayBuffer;
 
 class FutexWaitListNode {
  public:
   FutexWaitListNode()
       : prev_(nullptr),
         next_(nullptr),
         backing_store_(nullptr),
         wait_addr_(0),
         waiting_(false) {}
 
@@ skipping 70 matching lines @@
                                       size_t addr);
 
  private:
   static base::LazyMutex mutex_;
   static base::LazyInstance<FutexWaitList>::type wait_list_;
 };
 }
 }  // namespace v8::internal
 
 #endif  // V8_FUTEX_EMULATION_H_