Update from https://crrev.com/327068

base/compiler_specific.h

 // Copyright (c) 2012 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 BASE_COMPILER_SPECIFIC_H_
 #define BASE_COMPILER_SPECIFIC_H_
 
 #include "build/build_config.h"
 
 #if defined(COMPILER_MSVC)
@@ skipping 110 matching lines @@
 // Specify memory alignment for structs, classes, etc.
 // Use like:
 //   class ALIGNAS(16) MyClass { ... }
 //   ALIGNAS(16) int array[4];
 #if defined(COMPILER_MSVC)
 #define ALIGNAS(byte_alignment) __declspec(align(byte_alignment))
 #elif defined(COMPILER_GCC)
 #define ALIGNAS(byte_alignment) __attribute__((aligned(byte_alignment)))
 #endif
 
-// Return the byte alignment of the given type (available at compile time).  Use
-// sizeof(type) prior to checking __alignof to workaround Visual C++ bug:
-// http://goo.gl/isH0C
+// Return the byte alignment of the given type (available at compile time).
 // Use like:
 //   ALIGNOF(int32)  // this would be 4
 #if defined(COMPILER_MSVC)
-#define ALIGNOF(type) (sizeof(type) - sizeof(type) + __alignof(type))
+#define ALIGNOF(type) __alignof(type)
 #elif defined(COMPILER_GCC)
 #define ALIGNOF(type) __alignof__(type)
 #endif
 
 // Annotate a function indicating the caller must examine the return value.
 // Use like:
 //   int foo() WARN_UNUSED_RESULT;
 // To explicitly ignore a result, see |ignore_result()| in <base/basictypes.h>.
 #if defined(COMPILER_GCC)
 #define WARN_UNUSED_RESULT __attribute__((warn_unused_result))
@@ skipping 52 matching lines @@
 // Macro for hinting that an expression is likely to be false.
 #if !defined(UNLIKELY)
 #if defined(COMPILER_GCC)
 #define UNLIKELY(x) __builtin_expect(!!(x), 0)
 #else
 #define UNLIKELY(x) (x)
 #endif  // defined(COMPILER_GCC)
 #endif  // !defined(UNLIKELY)
 
 #endif  // BASE_COMPILER_SPECIFIC_H_