Fix C++ type of Factory::NewFixedDoubleArray.

src/factory.h

Index: src/factory.h
diff --git a/src/factory.h b/src/factory.h
index f29aac4aa8fee8dd43d48712bf562040e44f0f6a..72f8a015623cb5158dfaf1fe853c02ffa13d2efb 100644
--- a/src/factory.h
+++ b/src/factory.h
@@ -33,12 +33,12 @@ class Factory V8_FINAL {
   Handle<FixedArray> NewUninitializedFixedArray(int size);
 
   // Allocate a new uninitialized fixed double array.
-  Handle<FixedDoubleArray> NewFixedDoubleArray(
+  Handle<FixedArrayBase> NewFixedDoubleArray(
       int size,
       PretenureFlag pretenure = NOT_TENURED);
 
   // Allocate a new fixed double array with hole values.
-  Handle<FixedDoubleArray> NewFixedDoubleArrayWithHoles(
+  Handle<FixedArrayBase> NewFixedDoubleArrayWithHoles(
       int size,
       PretenureFlag pretenure = NOT_TENURED);