Revert "[heap] Use RAIL mode for initial heap sizing"

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 2dc44d9355b4fa3977346329120cf61bf3a985ad..42a5a55b9d622a39ecf8cea37bcf555a7329b47f 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -2112,7 +2112,6 @@ Isolate::Isolate(bool enable_serializer)
       // be fixed once the default isolate cleanup is done.
       random_number_generator_(NULL),
       rail_mode_(PERFORMANCE_ANIMATION),
-      load_start_time_ms_(0),
       serializer_enabled_(enable_serializer),
       has_fatal_error_(false),
       initialized_from_snapshot_(false),
@@ -3442,22 +3441,8 @@ void Isolate::CheckDetachedContextsAfterGC() {
   }
 }
 
-double Isolate::LoadStartTimeMs() {
-  base::LockGuard<base::Mutex> guard(&rail_mutex_);
-  return load_start_time_ms_;
-}
-
 void Isolate::SetRAILMode(RAILMode rail_mode) {
-  RAILMode old_rail_mode = rail_mode_.Value();
-  if (old_rail_mode != PERFORMANCE_LOAD && rail_mode == PERFORMANCE_LOAD) {
-    base::LockGuard<base::Mutex> guard(&rail_mutex_);
-    load_start_time_ms_ = heap()->MonotonicallyIncreasingTimeInMs();
-  }
   rail_mode_.SetValue(rail_mode);
-  if (old_rail_mode == PERFORMANCE_LOAD && rail_mode != PERFORMANCE_LOAD) {
-    heap()->incremental_marking()->incremental_marking_job()->ScheduleTask(
-        heap());
-  }
   if (FLAG_trace_rail) {
     PrintIsolate(this, "RAIL mode: %s\n", RAILModeName(rail_mode));
   }