Add out-of-process memory logging stream parsing.

chrome/common/profiling/memlog_stream.h

 // Copyright 2017 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 CHROME_COMMON_PROFILING_MEMLOG_STREAM_H_
 #define CHROME_COMMON_PROFILING_MEMLOG_STREAM_H_
 
+#include <stdint.h>
+
 #include "build/build_config.h"
 
 namespace profiling {
 
+static const uint32_t kStreamSignature = 0xF6103B71;
+
+static const uint32_t kAllocPacketType = 0xA1A1A1A1;
+static const uint32_t kFreePacketType = 0xFEFEFEFE;
+
+#pragma pack(push, 1)
+struct StreamHeader {
+  uint32_t signature;  // kStreamSignature
+};
+
+struct AllocPacket {
+  uint32_t op;  // = kAllocPacketType
+
+  uint64_t time;
+  uint64_t address;
+  uint64_t size;
+
+  uint32_t stack_len;
+  // Immediately followed by |stack_len| more addresses.
+};
+
+struct FreePacket {
+  uint32_t op;  // = kFreePacketType
+
+  uint64_t time;
+  uint64_t address;
+};
+#pragma pack(pop)
+
 #if defined(OS_WIN)
 // Prefix for pipe name for communicating between chrome processes and the
 // memlog process. The pipe ID is appended to this to get the pipe name.
 extern const wchar_t kWindowsPipePrefix[];
 #endif  // OS_WIN
 
 }  // namespace profiling
 
 #endif  // CHROME_COMMON_PROFILING_MEMLOG_STREAM_H_