Don't define ARRAYSIZE_UNSAFE except in Blink.

base/macros.h

 // Copyright 2014 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.
 
 // This file contains macros and macro-like constructs (e.g., templates) that
 // are commonly used throughout Chromium source. (It may also contain things
 // that are closely related to things that are commonly used that belong in this
 // file.)
 
 #ifndef BASE_MACROS_H_
@@ skipping 51 matching lines @@
 // template overloads: the final frontier.
 #ifndef _MSC_VER
 template <typename T, size_t N>
 char (&ArraySizeHelper(const T (&array)[N]))[N];
 #endif
 
 #define arraysize(array) (sizeof(ArraySizeHelper(array)))
 
 // DEPRECATED: Just use |arraysize()|, now that C++11 has removed the
 // limitations that forced the use of |ARRAYSIZE_UNSAFE()|.
-// TODO(viettrungluu): Convert all instances and delete. crbug.com/423134
+// TODO(viettrungluu): Convert all instances and delete. (The only uses are now
+// in Blink; the ifdef is to prevent it from reappearing in Chromium.)
+// crbug.com/423134
+#if defined(BLINK_PLATFORM) || defined(BLINK_PLATFORM_IMPLEMENTATION)
 #define ARRAYSIZE_UNSAFE(a) arraysize(a)
+#endif
 
 
 // Use implicit_cast as a safe version of static_cast or const_cast
 // for upcasting in the type hierarchy (i.e. casting a pointer to Foo
 // to a pointer to SuperclassOfFoo or casting a pointer to Foo to
 // a const pointer to Foo).
 // When you use implicit_cast, the compiler checks that the cast is safe.
 // Such explicit implicit_casts are necessary in surprisingly many
 // situations where C++ demands an exact type match instead of an
 // argument type convertible to a target type.
@@ skipping 122 matching lines @@
 
 // Use these to declare and define a static local variable (static T;) so that
 // it is leaked so that its destructors are not called at exit. If you need
 // thread-safe initialization, use base/lazy_instance.h instead.
 #define CR_DEFINE_STATIC_LOCAL(type, name, arguments) \
   static type& name = *new type arguments
 
 }  // base
 
 #endif  // BASE_MACROS_H_