Revert of Move BenchTimer to tools as Timer

tools/timer/SysTimer_posix.cpp

Index: tools/timer/SysTimer_posix.cpp
diff --git a/tools/timer/SysTimer_posix.cpp b/tools/timer/SysTimer_posix.cpp
deleted file mode 100644
index 4b7d708aab0c4a7e899da8c55ddb409f43845a16..0000000000000000000000000000000000000000
--- a/tools/timer/SysTimer_posix.cpp
+++ /dev/null
@@ -1,51 +0,0 @@
-/*
- * Copyright 2011 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-#include "SysTimer_posix.h"
-
-static double interval_in_ms(timespec start_clock, timespec end_clock)
-{
-    double duration_clock;
-    if ((end_clock.tv_nsec - start_clock.tv_nsec) < 0) {
-        duration_clock = (end_clock.tv_sec - start_clock.tv_sec - 1) * 1000;
-        duration_clock += (1000000000 + end_clock.tv_nsec - start_clock.tv_nsec) / 1000000.0;
-    } else {
-        duration_clock = (end_clock.tv_sec - start_clock.tv_sec) * 1000;
-        duration_clock += (end_clock.tv_nsec - start_clock.tv_nsec) / 1000000.0;
-    }
-    return duration_clock;
-}
-
-void SysTimer::startWall() {
-    if (-1 == clock_gettime(CLOCK_MONOTONIC, &fWall)) {
-        timespec none = {0, 0};
-        fWall = none;
-    }
-}
-void SysTimer::startCpu() {
-    if (-1 == clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &fCpu)) {
-        timespec none = {0, 0};
-        fCpu = none;
-    }
-}
-
-double SysTimer::endCpu() {
-    timespec end_cpu;
-    if (-1 == clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &end_cpu)) {
-        timespec none = {0, 0};
-        end_cpu = none;
-    }
-    return interval_in_ms(fCpu, end_cpu);
-}
-
-double SysTimer::endWall() {
-    timespec end_wall;
-    if (-1 == clock_gettime(CLOCK_MONOTONIC, &end_wall)) {
-        timespec none = {0, 0};
-        end_wall = none;
-    }
-    return interval_in_ms(fWall, end_wall);
-}