Cleanup: Replace 'DurationInt' with int32, and always use 32-bit integers for tracking time.

base/profiler/tracked_time.cc

Index: base/profiler/tracked_time.cc
diff --git a/base/profiler/tracked_time.cc b/base/profiler/tracked_time.cc
index 0e227bd4dbcf252a5618c4ae536211d00f0d2e62..3c51081e3c0780ac722d319cb8446fe92dea8244 100644
--- a/base/profiler/tracked_time.cc
+++ b/base/profiler/tracked_time.cc
@@ -12,8 +12,6 @@
 
 namespace tracked_objects {
 
-#if defined(USE_FAST_TIME_CLASS_FOR_DURATION_CALCULATIONS)
-
 Duration::Duration() : ms_(0) {}
 Duration::Duration(int32 duration) : ms_(duration) {}
 
@@ -75,6 +73,4 @@ TrackedTime TrackedTime::operator+(const Duration& other) const {
 
 bool TrackedTime::is_null() const { return ms_ == 0; }
 
-#endif  // USE_FAST_TIME_CLASS_FOR_DURATION_CALCULATIONS
-
 }  // namespace tracked_objects