Revert of SkTime::GetNSecs()

tools/timer/Timer.cpp

 /*
  * 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 "Timer.h"
 
+Timer::Timer(SkGLContext* gl)
+        : fCpu(-1.0)
+        , fWall(-1.0)
+        , fTruncatedCpu(-1.0)
+        , fTruncatedWall(-1.0)
+        , fGpu(-1.0)
+#if SK_SUPPORT_GPU
+        , fGpuTimer(gl)
+#endif
+        {}
+
+void Timer::start() {
+    fSysTimer.startWall();
+    fTruncatedSysTimer.startWall();
+#if SK_SUPPORT_GPU
+    fGpuTimer.start();
+#endif
+    fSysTimer.startCpu();
+    fTruncatedSysTimer.startCpu();
+}
+
+void Timer::end() {
+    fCpu = fSysTimer.endCpu();
+#if SK_SUPPORT_GPU
+    //It is important to stop the cpu clocks first,
+    //as the following will cpu wait for the gpu to finish.
+    fGpu = fGpuTimer.end();
+#endif
+    fWall = fSysTimer.endWall();
+}
+
+void Timer::truncatedEnd() {
+    fTruncatedCpu = fTruncatedSysTimer.endCpu();
+    fTruncatedWall = fTruncatedSysTimer.endWall();
+}
+
+WallTimer::WallTimer() : fWall(-1.0) {}
+
+void WallTimer::start() {
+    fSysTimer.startWall();
+}
+
+void WallTimer::end() {
+    fWall = fSysTimer.endWall();
+}
+
 SkString HumanizeMs(double ms) {
     if (ms > 60e+3)  return SkStringPrintf("%.3gm", ms/60e+3);
     if (ms >  1e+3)  return SkStringPrintf("%.3gs",  ms/1e+3);
     if (ms <  1e-3)  return SkStringPrintf("%.3gns", ms*1e+6);
 #ifdef SK_BUILD_FOR_WIN
     if (ms < 1)      return SkStringPrintf("%.3gus", ms*1e+3);
 #else
     if (ms < 1)      return SkStringPrintf("%.3gµs", ms*1e+3);
 #endif
     return SkStringPrintf("%.3gms", ms);
 }