profiler: cleanup unused alternate_timer code

base/tracked_objects.cc

Index: base/tracked_objects.cc
diff --git a/base/tracked_objects.cc b/base/tracked_objects.cc
index 0632edf71e5725a34962ff28a1ea67f7b327f0ec..33a0a27ef6763524eb05b281138fb1bc0244e75e 100644
--- a/base/tracked_objects.cc
+++ b/base/tracked_objects.cc
@@ -14,7 +14,6 @@
 #include "base/debug/leak_annotations.h"
 #include "base/logging.h"
 #include "base/process/process_handle.h"
-#include "base/profiler/alternate_timer.h"
 #include "base/strings/stringprintf.h"
 #include "base/third_party/valgrind/memcheck.h"
 #include "base/tracking_info.h"
@@ -285,7 +284,7 @@ void Births::RecordBirth() { ++birth_count_; }
 // to them.
 
 // static
-NowFunction* ThreadData::now_function_ = NULL;
+ThreadData::NowFunction* ThreadData::now_function_ = NULL;
 
 // static
 bool ThreadData::now_function_is_time_ = false;
@@ -692,12 +691,6 @@ void ThreadData::OnProfilingPhaseCompletedOnThread(int profiling_phase) {
   }
 }
 
-static void OptionallyInitializeAlternateTimer() {
-  NowFunction* alternate_time_source = GetAlternateTimeSource();
-  if (alternate_time_source)
-    ThreadData::SetAlternateTimeSource(alternate_time_source);
-}
-
 void ThreadData::Initialize() {
   if (base::subtle::Acquire_Load(&status_) >= DEACTIVATED)
     return;  // Someone else did the initialization.
@@ -711,13 +704,6 @@ void ThreadData::Initialize() {
   if (base::subtle::Acquire_Load(&status_) >= DEACTIVATED)
     return;  // Someone raced in here and beat us.
 
-  // Put an alternate timer in place if the environment calls for it, such as
-  // for tracking TCMalloc allocations.  This insertion is idempotent, so we
-  // don't mind if there is a race, and we'd prefer not to be in a lock while
-  // doing this work.
-  if (kAllowAlternateTimeSourceHandling)
-    OptionallyInitializeAlternateTimer();
-
   // Perform the "real" TLS initialization now, and leave it intact through
   // process termination.
   if (!tls_index_.initialized()) {  // Testing may have initialized this.