Handlify six allocator functions from the Heap.

src/factory.h

Index: src/factory.h
diff --git a/src/factory.h b/src/factory.h
index e838ec6a41da784f4ce1648262f58692d8faa3aa..a011e6649e2a5f9c9c0c87852eb1f09655a44ee2 100644
--- a/src/factory.h
+++ b/src/factory.h
@@ -67,9 +67,11 @@ class Factory V8_FINAL {
   Handle<DeoptimizationOutputData> NewDeoptimizationOutputData(
       int deopt_entry_count,
       PretenureFlag pretenure);
-  // Allocates a pre-tenured empty AccessorPair.
+
+  // Create a pre-tenured empty AccessorPair.
   Handle<AccessorPair> NewAccessorPair();
 
+  // Create an empty TypeFeedbackInfo.
   Handle<TypeFeedbackInfo> NewTypeFeedbackInfo();
 
   Handle<String> InternalizeUtf8String(Vector<const char> str);
@@ -396,8 +398,10 @@ class Factory V8_FINAL {
       Handle<Context> context,
       PretenureFlag pretenure = TENURED);
 
+  // Create a serialized scope info.
   Handle<ScopeInfo> NewScopeInfo(int length);
 
+  // Create an External object for V8's external API.
   Handle<JSObject> NewExternal(void* value);
 
   Handle<Code> NewCode(const CodeDesc& desc,