Revert r14930 and r14935 temporarily.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index b95af11ae01c5a184dcf25f0b89eceeac32eded2..4243bcab442dba760215358d3b707617185f8adf 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -4421,7 +4421,10 @@ MaybeObject* Heap::AllocateJSObjectFromMap(Map* map, PretenureFlag pretenure) {
   ASSERT(map->instance_type() != JS_BUILTINS_OBJECT_TYPE);
 
   // Allocate the backing storage for the properties.
-  int prop_size = map->InitialPropertiesLength();
+  int prop_size =
+      map->pre_allocated_property_fields() +
+      map->unused_property_fields() -
+      map->inobject_properties();
   ASSERT(prop_size >= 0);
   Object* properties;
   { MaybeObject* maybe_properties = AllocateFixedArray(prop_size, pretenure);
@@ -4458,7 +4461,10 @@ MaybeObject* Heap::AllocateJSObjectFromMapWithAllocationSite(Map* map,
   ASSERT(map->instance_type() != JS_BUILTINS_OBJECT_TYPE);
 
   // Allocate the backing storage for the properties.
-  int prop_size = map->InitialPropertiesLength();
+  int prop_size =
+      map->pre_allocated_property_fields() +
+      map->unused_property_fields() -
+      map->inobject_properties();
   ASSERT(prop_size >= 0);
   Object* properties;
   { MaybeObject* maybe_properties = AllocateFixedArray(prop_size);
@@ -6645,7 +6651,12 @@ bool Heap::ConfigureHeap(int max_semispace_size,
   max_semispace_size_ = RoundUpToPowerOf2(max_semispace_size_);
   reserved_semispace_size_ = RoundUpToPowerOf2(reserved_semispace_size_);
   initial_semispace_size_ = Min(initial_semispace_size_, max_semispace_size_);
-  external_allocation_limit_ = 16 * max_semispace_size_;
+
+  // The external allocation limit should be below 256 MB on all architectures
+  // to avoid unnecessary low memory notifications, as that is the threshold
+  // for some embedders.
+  external_allocation_limit_ = 12 * max_semispace_size_;
+  ASSERT(external_allocation_limit_ <= 256 * MB);
 
   // The old generation is paged and needs at least one page for each space.
   int paged_space_count = LAST_PAGED_SPACE - FIRST_PAGED_SPACE + 1;