Fixit: Fork base::TimeTicks --> TimeTicks + ThreadTicks + TraceTicks

base/time/time.h

Index: base/time/time.h
diff --git a/base/time/time.h b/base/time/time.h
index 0a2677838617e79ada4b219cc684631cf799a519..9b195975fbc9225105f9f5433cb53e9d925069a8 100644
--- a/base/time/time.h
+++ b/base/time/time.h
@@ -639,14 +639,6 @@ BASE_EXPORT std::ostream& operator<<(std::ostream& os, Time time);
 // Represents monotonically non-decreasing clock time.
 class BASE_EXPORT TimeTicks : public time_internal::TimeBase<TimeTicks> {
  public:
-  // We define this even without OS_CHROMEOS for seccomp sandbox testing.
-#if defined(OS_LINUX)
-  // Force definition of the system trace clock; it is a chromeos-only api
-  // at the moment and surfacing it in the right place requires mucking
-  // with glibc et al.
-  static const clockid_t kClockSystemTrace = 11;
-#endif
-
   TimeTicks() : TimeBase(0) {
   }
 
@@ -662,43 +654,6 @@ class BASE_EXPORT TimeTicks : public time_internal::TimeBase<TimeTicks> {
   // clock will be used instead.
   static bool IsHighResolution();
 
-  // Returns true if ThreadNow() is supported on this system.
-  static bool IsThreadNowSupported() {
-#if (defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
-    (defined(OS_MACOSX) && !defined(OS_IOS)) || defined(OS_ANDROID)
-    return true;
-#else
-    return false;
-#endif
-  }
-
-  // Returns thread-specific CPU-time on systems that support this feature.
-  // Needs to be guarded with a call to IsThreadNowSupported(). Use this timer
-  // to (approximately) measure how much time the calling thread spent doing
-  // actual work vs. being de-scheduled. May return bogus results if the thread
-  // migrates to another CPU between two calls.
-  //
-  // WARNING: The returned value might NOT have the same origin as Now(). Do not
-  // perform math between TimeTicks values returned by Now() and ThreadNow() and
-  // expect meaningful results.
-  // TODO(miu): Since the timeline of these values is different, the values
-  // should be of a different type.
-  static TimeTicks ThreadNow();
-
-  // Returns the current system trace time or, if not available on this
-  // platform, a high-resolution time value; or a low-resolution time value if
-  // neither are avalable. On systems where a global trace clock is defined,
-  // timestamping TraceEvents's with this value guarantees synchronization
-  // between events collected inside chrome and events collected outside
-  // (e.g. kernel, X server).
-  //
-  // WARNING: The returned value might NOT have the same origin as Now(). Do not
-  // perform math between TimeTicks values returned by Now() and
-  // NowFromSystemTraceTime() and expect meaningful results.
-  // TODO(miu): Since the timeline of these values is different, the values
-  // should be of a different type.
-  static TimeTicks NowFromSystemTraceTime();
-
 #if defined(OS_WIN)
   // Translates an absolute QPC timestamp into a TimeTicks value. The returned
   // value has the same origin as Now(). Do NOT attempt to use this if
@@ -738,6 +693,80 @@ class BASE_EXPORT TimeTicks : public time_internal::TimeBase<TimeTicks> {
 // For logging use only.
 BASE_EXPORT std::ostream& operator<<(std::ostream& os, TimeTicks time_ticks);
 
+// ThreadTicks ----------------------------------------------------------------
+
+// Represents a clock, specific to a particular thread, than runs only while the
+// thread is running.
+class BASE_EXPORT ThreadTicks : public time_internal::TimeBase<ThreadTicks> {
+ public:
+  ThreadTicks() : TimeBase(0) {
+  }
+
+  // Returns true if ThreadTicks::Now() is supported on this system.
+  static bool IsSupported() {
+#if (defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
+    (defined(OS_MACOSX) && !defined(OS_IOS)) || defined(OS_ANDROID)
+    return true;
+#else
+    return false;
+#endif
+  }
+
+  // Returns thread-specific CPU-time on systems that support this feature.
+  // Needs to be guarded with a call to IsSupported(). Use this timer
+  // to (approximately) measure how much time the calling thread spent doing
+  // actual work vs. being de-scheduled. May return bogus results if the thread
+  // migrates to another CPU between two calls.
+  static ThreadTicks Now();
+
+ private:
+  friend class time_internal::TimeBase<ThreadTicks>;
+
+  // Please use Now() to create a new object. This is for internal use
+  // and testing.
+  explicit ThreadTicks(int64 us) : TimeBase(us) {
+  }
+};
+
+// For logging use only.
+BASE_EXPORT std::ostream& operator<<(std::ostream& os, ThreadTicks time_ticks);
+
+// TraceTicks ----------------------------------------------------------------
+
+// Represents high-resolution system trace clock time.
+class BASE_EXPORT TraceTicks : public time_internal::TimeBase<TraceTicks> {
+ public:
+  // We define this even without OS_CHROMEOS for seccomp sandbox testing.
+#if defined(OS_LINUX)
+  // Force definition of the system trace clock; it is a chromeos-only api
+  // at the moment and surfacing it in the right place requires mucking
+  // with glibc et al.
+  static const clockid_t kClockSystemTrace = 11;
+#endif
+
+  TraceTicks() : TimeBase(0) {
+  }
+
+  // Returns the current system trace time or, if not available on this
+  // platform, a high-resolution time value; or a low-resolution time value if
+  // neither are avalable. On systems where a global trace clock is defined,
+  // timestamping TraceEvents's with this value guarantees synchronization
+  // between events collected inside chrome and events collected outside
+  // (e.g. kernel, X server).
+  static TraceTicks Now();
+
+ private:
+  friend class time_internal::TimeBase<TraceTicks>;
+
+  // Please use Now() to create a new object. This is for internal use
+  // and testing.
+  explicit TraceTicks(int64 us) : TimeBase(us) {
+  }
+};
+
+// For logging use only.
+BASE_EXPORT std::ostream& operator<<(std::ostream& os, TraceTicks time_ticks);
+
 }  // namespace base
 
 #endif  // BASE_TIME_TIME_H_