Partially revert https://crrev.com/7e53749df0a10f475404e86ef0ca8df02bb79e7a

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index e37c9f6b11de8b333743e8f296486d3561721013..4647157e8e3443275064997d92c326207fe297cc 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -4763,7 +4763,13 @@ bool Heap::HasHighFragmentation(intptr_t used, intptr_t committed) {
 
 
 void Heap::ReduceNewSpaceSize() {
-  if (!FLAG_predictable && HasLowAllocationRate()) {
+  // TODO(ulan): Unify this constant with the similar constant in
+  // GCIdleTimeHandler once the change is merged to 4.5.
+  static const size_t kLowAllocationThroughput = 1000;
+  size_t allocation_throughput =
+      tracer()->CurrentAllocationThroughputInBytesPerMillisecond();
+  if (FLAG_predictable || allocation_throughput == 0) return;
+  if (allocation_throughput < kLowAllocationThroughput) {
     new_space_.Shrink();
     UncommitFromSpace();
   }