disable assembly in header for msan=1

include/libyuv/scale_row.h

 /*
  *  Copyright 2013 The LibYuv 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 in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS. All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef INCLUDE_LIBYUV_SCALE_ROW_H_  // NOLINT
 #define INCLUDE_LIBYUV_SCALE_ROW_H_
 
 #include "libyuv/basic_types.h"
 #include "libyuv/scale.h"
 
 #ifdef __cplusplus
 namespace libyuv {
 extern "C" {
 #endif
 
 #if defined(__pnacl__) || defined(__CLR_VER) || \
     (defined(__i386__) && !defined(__SSE2__))
 #define LIBYUV_DISABLE_X86
 #endif
+// MemorySanitizer does not support assembly code yet. http://crbug.com/344505
+#if defined(__has_feature)
+#if __has_feature(memory_sanitizer)
+#define LIBYUV_DISABLE_X86
+#endif
+#endif
 
 // GCC >= 4.7.0 required for AVX2.
 #if defined(__GNUC__) && (defined(__x86_64__) || defined(__i386__))
 #if (__GNUC__ > 4) || (__GNUC__ == 4 && (__GNUC_MINOR__ >= 7))
 #define GCC_HAS_AVX2 1
 #endif  // GNUC >= 4.7
 #endif  // __GNUC__
 
 // clang >= 3.4.0 required for AVX2.
 #if defined(__clang__) && (defined(__x86_64__) || defined(__i386__))
@@ skipping 452 matching lines @@
                                 uint8* dst_ptr, int dst_width);
 void ScaleRowDown38_3_Box_DSPR2(const uint8* src_ptr, ptrdiff_t src_stride,
                                 uint8* dst_ptr, int dst_width);
 
 #ifdef __cplusplus
 }  // extern "C"
 }  // namespace libyuv
 #endif
 
 #endif  // INCLUDE_LIBYUV_SCALE_ROW_H_  NOLINT