Revert "Remove flag track-allocation-sites."

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 9b45b3134c4ed283e60499d41e91b9d50177d62a..aa7f500c8a36198355b85b37a4ae11484f87a15f 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -9191,24 +9191,26 @@ AllocationMemento* AllocationMemento::FindForHeapObject(HeapObject* object,
   // checking the object immediately after the current object (if there is one)
   // to see if it's an AllocationMemento.
   ASSERT(object->GetHeap()->InNewSpace(object));
-  Address ptr_end = (reinterpret_cast<Address>(object) - kHeapObjectTag) +
-      object->Size();
-  Address top;
-  if (in_GC) {
-    top = object->GetHeap()->new_space()->FromSpacePageHigh();
-  } else {
-    top = object->GetHeap()->NewSpaceTop();
-  }
-  if ((ptr_end + AllocationMemento::kSize) <= top) {
-    // There is room in newspace for allocation info. Do we have some?
-    Map** possible_allocation_memento_map =
-        reinterpret_cast<Map**>(ptr_end);
-    if (*possible_allocation_memento_map ==
-        object->GetHeap()->allocation_memento_map()) {
-      AllocationMemento* memento = AllocationMemento::cast(
-          reinterpret_cast<Object*>(ptr_end + kHeapObjectTag));
-      if (memento->IsValid()) {
-        return memento;
+  if (FLAG_track_allocation_sites) {
+    Address ptr_end = (reinterpret_cast<Address>(object) - kHeapObjectTag) +
+        object->Size();
+    Address top;
+    if (in_GC) {
+      top = object->GetHeap()->new_space()->FromSpacePageHigh();
+    } else {
+      top = object->GetHeap()->NewSpaceTop();
+    }
+    if ((ptr_end + AllocationMemento::kSize) <= top) {
+      // There is room in newspace for allocation info. Do we have some?
+      Map** possible_allocation_memento_map =
+          reinterpret_cast<Map**>(ptr_end);
+      if (*possible_allocation_memento_map ==
+          object->GetHeap()->allocation_memento_map()) {
+        AllocationMemento* memento = AllocationMemento::cast(
+            reinterpret_cast<Object*>(ptr_end + kHeapObjectTag));
+        if (memento->IsValid()) {
+          return memento;
+        }
       }
     }
   }
@@ -12893,7 +12895,7 @@ void JSObject::UpdateAllocationSite(Handle<JSObject> object,
 
 
 MaybeObject* JSObject::UpdateAllocationSite(ElementsKind to_kind) {
-  if (!IsJSArray()) {
+  if (!FLAG_track_allocation_sites || !IsJSArray()) {
     return this;
   }