profiler: cleanup unused alternate_timer code

base/tracked_objects.h

Index: base/tracked_objects.h
diff --git a/base/tracked_objects.h b/base/tracked_objects.h
index 1a00ec0be05ec5e999abb52d5de74ef4fe609564..38d2702ff81a3e6890a2300eff185fdfa99778bb 100644
--- a/base/tracked_objects.h
+++ b/base/tracked_objects.h
@@ -22,7 +22,6 @@
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/process/process_handle.h"
-#include "base/profiler/alternate_timer.h"
 #include "base/profiler/tracked_time.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_checker.h"
@@ -537,12 +536,6 @@ class BASE_EXPORT ThreadData {
   // the code).
   static TrackedTime Now();
 
-  // Use the function |now| to provide current times, instead of calling the
-  // TrackedTime::Now() function.  Since this alternate function is being used,
-  // the other time arguments (used for calculating queueing delay) will be
-  // ignored.
-  static void SetAlternateTimeSource(NowFunction* now);
-
   // This function can be called at process termination to validate that thread
   // cleanup routines have been called for at least some number of named
   // threads.
@@ -559,8 +552,8 @@ class BASE_EXPORT ThreadData {
   FRIEND_TEST_ALL_PREFIXES(TrackedObjectsTest, MinimalStartupShutdown);
   FRIEND_TEST_ALL_PREFIXES(TrackedObjectsTest, TinyStartupShutdown);
 
+  typedef unsigned int NowFunction();  // Type for an alternate timer function.

[Ilya Sherman, 2016/02/01 19:24:52]

nit: Mebbe update the comment to indicate that this is just used for testing.

   typedef std::map<const BirthOnThread*, int> BirthCountMap;
-
   typedef std::vector<std::pair<const Births*, DeathDataPhaseSnapshot>>
       DeathsSnapshot;
 
@@ -635,11 +628,7 @@ class BASE_EXPORT ThreadData {
 
   // When non-null, this specifies an external function that supplies monotone
   // increasing time functcion.
-  static NowFunction* now_function_;
-
-  // If true, now_function_ returns values that can be used to calculate queue
-  // time.
-  static bool now_function_is_time_;
+  static NowFunction* now_function_for_testing_;
 
   // We use thread local store to identify which ThreadData to interact with.
   static base::ThreadLocalStorage::StaticSlot tls_index_;