Drop (empty) virtual destructor from Iterable<> class

Source/core/dom/Iterable.h

 // Copyright 2015 The Chromium 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 Iterable_h
 #define Iterable_h
 
 #include "bindings/core/v8/V8IteratorResultValue.h"
 #include "core/dom/Iterator.h"
 
 namespace blink {
 
 // Typically, use one of ValueIterable<> and PairIterable<> (below) instead!
 template <typename KeyType, typename ValueType>
 class Iterable {
 public:
-    virtual ~Iterable() { }
-
     Iterator* keys(ScriptState* scriptState, ExceptionState& exceptionState)
     {
         IterationSource* source = this->startIteration(scriptState, exceptionState);
         if (!source)
             return nullptr;
         return new IterableIterator<KeySelector>(source);
     }
 
     Iterator* values(ScriptState* scriptState, ExceptionState& exceptionState)
     {
@@ skipping 129 matching lines @@
 public:
     Iterator* iterator(ScriptState* scriptState, ExceptionState& exceptionState)
     {
         return this->entries(scriptState, exceptionState);
     }
 };
 
 } // namespace blink
 
 #endif // Iterable_h