Benchmark tools: Android memtrack_helper meaningful errors.

tools/android/memtrack_helper/memtrack_helper.h

 /*
  * Copyright 2015 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 TOOLS_ANDROID_MEMTRACK_HELPER_H_
 #define TOOLS_ANDROID_MEMTRACK_HELPER_H_
 
+#include <android/log.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 
 static inline void exit_with_failure(const char* reason) {
   perror(reason);
+  __android_log_write(ANDROID_LOG_ERROR, "memtrack_helper", reason);
   exit(EXIT_FAILURE);
 }
 
 static inline void init_memtrack_server_addr(struct sockaddr_un* addr) {
   const char* const kAbstractSocketName = "chrome_tracing_memtrack_helper";
   memset(addr, 0, sizeof(*addr));
   addr->sun_family = AF_UNIX;
   strncpy(&addr->sun_path[1], kAbstractSocketName, sizeof(addr->sun_path) - 2);
 }
 
 #endif  // TOOLS_ANDROID_MEMTRACK_HELPER_H_