Fix gcc error for static_cast the parameters of DCHECK_GT macro to unsigned in list.h.

src/list.h

 // Copyright 2011 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_LIST_H_
 #define V8_LIST_H_
 
 #include <algorithm>
 
 #include "src/checks.h"
@@ skipping 47 matching lines @@
   // Please the MSVC compiler.  We should never have to execute this.
   INLINE(void operator delete(void* p, AllocationPolicy allocator)) {
     UNREACHABLE();
   }
 
   // Returns a reference to the element at index i.  This reference is
   // not safe to use after operations that can change the list's
   // backing store (e.g. Add).
   inline T& operator[](int i) const {
     DCHECK_LE(0, i);
-    DCHECK_GT(length_, i);
+    DCHECK_GT(static_cast<unsigned>(length_), static_cast<unsigned>(i));
     return data_[i];
   }
   inline T& at(int i) const { return operator[](i); }
   inline T& last() const { return at(length_ - 1); }
   inline T& first() const { return at(0); }
 
   typedef T* iterator;
   inline iterator begin() const { return &data_[0]; }
   inline iterator end() const { return &data_[length_]; }
 
@@ skipping 147 matching lines @@
 int SortedListBSearch(const List<T>& list, P cmp);
 template <typename T>
 int SortedListBSearch(const List<T>& list, T elem);
 
 
 }  // namespace internal
 }  // namespace v8
 
 
 #endif  // V8_LIST_H_