[snapshot] introduce SnapshotCreator API.

src/heap/heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/ast/scopeinfo.h"
 #include "src/base/bits.h"
@@ skipping 5591 matching lines @@
   DCHECK_EQ(*dep, LookupWeakObjectToCodeDependency(obj));
 }
 
 
 DependentCode* Heap::LookupWeakObjectToCodeDependency(Handle<HeapObject> obj) {
   Object* dep = weak_object_to_code_table()->Lookup(obj);
   if (dep->IsDependentCode()) return DependentCode::cast(dep);
   return DependentCode::cast(empty_fixed_array());
 }
 
+void Heap::CompactWeakFixedArrays() {
+  // Find known WeakFixedArrays and compact them.
+  i::HeapIterator iterator(this);
+  for (i::HeapObject* o = iterator.next(); o != NULL; o = iterator.next()) {
+    if (o->IsPrototypeInfo()) {
+      i::Object* prototype_users = i::PrototypeInfo::cast(o)->prototype_users();
+      if (prototype_users->IsWeakFixedArray()) {
+        i::WeakFixedArray* array = i::WeakFixedArray::cast(prototype_users);
+        array->Compact<i::JSObject::PrototypeRegistryCompactionCallback>();
+      }
+    } else if (o->IsScript()) {
+      i::Object* shared_list = i::Script::cast(o)->shared_function_infos();
+      if (shared_list->IsWeakFixedArray()) {
+        i::WeakFixedArray* array = i::WeakFixedArray::cast(shared_list);
+        array->Compact<i::WeakFixedArray::NullCallback>();
+      }
+    }
+  }
+}
 
 void Heap::AddRetainedMap(Handle<Map> map) {
   Handle<WeakCell> cell = Map::WeakCellForMap(map);
   Handle<ArrayList> array(retained_maps(), isolate());
   if (array->IsFull()) {
     CompactRetainedMaps(*array);
   }
   array = ArrayList::Add(
       array, cell, handle(Smi::FromInt(FLAG_retain_maps_for_n_gc), isolate()),
       ArrayList::kReloadLengthAfterAllocation);
@@ skipping 784 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8