Eliminate use of ZONE macro in BitVector class and pass a zone explicitly.

src/data-flow.h

Index: src/data-flow.h
===================================================================
--- src/data-flow.h	(revision 10788)
+++ src/data-flow.h	(working copy)
@@ -85,18 +85,18 @@
     friend class BitVector;
   };
 
-  explicit BitVector(int length)
+  BitVector(int length, Zone* zone)
       : length_(length),
         data_length_(SizeFor(length)),
-        data_(ZONE->NewArray<uint32_t>(data_length_)) {
+        data_(zone->NewArray<uint32_t>(data_length_)) {
     ASSERT(length > 0);
     Clear();
   }
 
-  BitVector(const BitVector& other)
+  BitVector(const BitVector& other, Zone* zone)
       : length_(other.length()),
         data_length_(SizeFor(length_)),
-        data_(ZONE->NewArray<uint32_t>(data_length_)) {
+        data_(zone->NewArray<uint32_t>(data_length_)) {
     CopyFrom(other);
   }