Update from https://crrev.com/320931

base/pickle.cc

 // 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.
 
 #include "base/pickle.h"
 
 #include <stdlib.h>
 
 #include <algorithm>  // for max()
 
@@ skipping 340 matching lines @@
   WriteBytesCommon(data, length);
 }
 
 template void Pickle::WriteBytesStatic<2>(const void* data);
 template void Pickle::WriteBytesStatic<4>(const void* data);
 template void Pickle::WriteBytesStatic<8>(const void* data);
 
 inline void Pickle::WriteBytesCommon(const void* data, size_t length) {
   DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
       << "oops: pickle is readonly";
+  MSAN_CHECK_MEM_IS_INITIALIZED(data, length);
   size_t data_len = AlignInt(length, sizeof(uint32));
   DCHECK_GE(data_len, length);
 #ifdef ARCH_CPU_64_BITS
   DCHECK_LE(data_len, kuint32max);
 #endif
   DCHECK_LE(write_offset_, kuint32max - data_len);
   size_t new_size = write_offset_ + data_len;
   if (new_size > capacity_after_header_) {
     Resize(std::max(capacity_after_header_ * 2, new_size));
   }
 
   char* write = mutable_payload() + write_offset_;
   memcpy(write, data, length);
   memset(write + length, 0, data_len - length);
   header_->payload_size = static_cast<uint32>(new_size);
   write_offset_ = new_size;
 }