Support weak heap references in the ConstantPool to support IsWeakObjectInOptimizedCode objects.

test/cctest/test-constantpool.cc

Index: test/cctest/test-constantpool.cc
diff --git a/test/cctest/test-constantpool.cc b/test/cctest/test-constantpool.cc
index e16e45a57d1658518aac9b9aa4e372437fbb9c15..eb35acd7ccb7ea24c86086421da21f8dd42020cc 100644
--- a/test/cctest/test-constantpool.cc
+++ b/test/cctest/test-constantpool.cc
@@ -28,10 +28,12 @@ TEST(ConstantPool) {
   v8::HandleScope scope(context->GetIsolate());
 
   // Check construction.
-  Handle<ConstantPoolArray> array = factory->NewConstantPoolArray(3, 1, 2, 1);
+  Handle<ConstantPoolArray> array =
+      factory->NewConstantPoolArray(3, 1, 2, 0, 1);
   CHECK_EQ(array->count_of_int64_entries(), 3);
   CHECK_EQ(array->count_of_code_ptr_entries(), 1);
   CHECK_EQ(array->count_of_heap_ptr_entries(), 2);
+  CHECK_EQ(array->count_of_weak_ptr_entries(), 0);
   CHECK_EQ(array->count_of_int32_entries(), 1);
   CHECK_EQ(array->length(), 7);
   CHECK_EQ(array->first_int64_index(), 0);