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

base/time/time_mac.cc

Index: base/time/time_mac.cc
diff --git a/base/time/time_mac.cc b/base/time/time_mac.cc
index e263d07945917f8acf2eb192c9b131c5366e5384..dcad44433589b1e2d63d70496ebdb9811f17bb59 100644
--- a/base/time/time_mac.cc
+++ b/base/time/time_mac.cc
@@ -13,6 +13,8 @@
 #include <sys/types.h>
 #include <time.h>
 
+#include <limits>
+
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/mac/mach_logging.h"
@@ -21,7 +23,7 @@
 
 namespace {
 
-uint64_t ComputeCurrentTicks() {
+int64 ComputeCurrentTicks() {
 #if defined(OS_IOS)
   // On iOS mach_absolute_time stops while the device is sleeping. Instead use
   // now - KERN_BOOTTIME to get a time difference that is not impacted by clock
@@ -59,15 +61,17 @@ uint64_t ComputeCurrentTicks() {
   absolute_micro =
       mach_absolute_time() / base::Time::kNanosecondsPerMicrosecond *
       timebase_info.numer / timebase_info.denom;
+  DCHECK_LE(absolute_micro,
+            static_cast<uint64_t>(std::numeric_limits<int64>::max()));
 
   // Don't bother with the rollover handling that the Windows version does.
   // With numer and denom = 1 (the expected case), the 64-bit absolute time
   // reported in nanoseconds is enough to last nearly 585 years.
-  return absolute_micro;
+  return static_cast<int64>(absolute_micro);
 #endif  // defined(OS_IOS)
 }
 
-uint64_t ComputeThreadTicks() {
+int64 ComputeThreadTicks() {
 #if defined(OS_IOS)
   NOTREACHED();
   return 0;
@@ -224,13 +228,13 @@ bool TimeTicks::IsHighResolution() {
 }
 
 // static
-TimeTicks TimeTicks::ThreadNow() {
-  return TimeTicks(ComputeThreadTicks());
+ThreadTicks ThreadTicks::Now() {
+  return ThreadTicks(ComputeThreadTicks());
 }
 
 // static
-TimeTicks TimeTicks::NowFromSystemTraceTime() {
-  return Now();
+TraceTicks TraceTicks::Now() {
+  return TraceTicks(ComputeCurrentTicks());
 }
 
 }  // namespace base