Revert of MSan: check data is initialized when serializing with base::Pickle.

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 157 matching lines @@
 // If available, it would look like:
 //   __attribute__((format(wprintf, format_param, dots_param)))
 
 // MemorySanitizer annotations.
 #if defined(MEMORY_SANITIZER) && !defined(OS_NACL)
 #include <sanitizer/msan_interface.h>
 
 // Mark a memory region fully initialized.
 // Use this to annotate code that deliberately reads uninitialized data, for
 // example a GC scavenging root set pointers from the stack.
-#define MSAN_UNPOISON(p, size)  __msan_unpoison(p, size)
-
-// Check a memory region for initializedness, as if it was being used here.
-// If any bits are uninitialized, crash with an MSan report.
-// Use this to sanitize data which MSan won't be able to track, e.g. before
-// passing data to another process via shared memory.
-#define MSAN_CHECK_MEM_IS_INITIALIZED(p, size) \
-    __msan_check_mem_is_initialized(p, size)
+#define MSAN_UNPOISON(p, s)  __msan_unpoison(p, s)
 #else  // MEMORY_SANITIZER
-#define MSAN_UNPOISON(p, size)
-#define MSAN_CHECK_MEM_IS_INITIALIZED(p, size)
+#define MSAN_UNPOISON(p, s)
 #endif  // MEMORY_SANITIZER
 
 // Macro useful for writing cross-platform function pointers.
 #if !defined(CDECL)
 #if defined(OS_WIN)
 #define CDECL __cdecl
 #else  // defined(OS_WIN)
 #define CDECL
 #endif  // defined(OS_WIN)
 #endif  // !defined(CDECL)
 
 // 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_