Android systrace: Optimize memory dumps.

systrace/atrace_helper/jni/logging.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 LOGGING_H_
 #define LOGGING_H_
 
 #include <android/log.h>
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <time.h>
 
 #define CHECK_ARGS(COND, ERR)                                          \
   "FAILED CHECK(%s) @ %s:%d (errno: %s)\n", #COND, __FILE__, __LINE__, \
       strerror(ERR)
 
 #define CHECK(x)                                              \
   do {                                                        \
     if (!(x)) {                                               \
       const int e = errno;                                    \
       __android_log_print(ANDROID_LOG_FATAL, "atrace_helper", \
                           CHECK_ARGS(x, e));                  \
       fprintf(stderr, "\n" CHECK_ARGS(x, e));                 \
       fflush(stderr);                                         \
       abort();                                                \
     }                                                         \
   } while (0)
 
 inline void LogError(const char* message) {
   __android_log_write(ANDROID_LOG_ERROR, "atrace_helper", message);
   fprintf(stderr, "\n%s\n", message);
   fflush(stderr);
 }
 
+inline uint64_t GetTimestamp() {
+  struct timespec ts = {};
+  CHECK(clock_gettime(CLOCK_MONOTONIC_COARSE, &ts) == 0);
+  return ts.tv_sec * 1000 + ts.tv_nsec / 1000000ul;
+}
+
 #endif  // LOGGING_H_