Fuchsia: Initial check-in.

runtime/vm/heap.h

Index: runtime/vm/heap.h
diff --git a/runtime/vm/heap.h b/runtime/vm/heap.h
index d13150ecdd30cd8667cf8a8ffee7f191b6a2caef..f0a956e26d10661722ed38aa50d35179dc720ae4 100644
--- a/runtime/vm/heap.h
+++ b/runtime/vm/heap.h
@@ -244,12 +244,14 @@ class Heap {
     return size <= kNewAllocatableSize;
   }
 
+#ifndef PRODUCT
   void PrintToJSONObject(Space space, JSONObject* object) const;
 
   // The heap map contains the sizes and class ids for the objects in each page.
   void PrintHeapMapToJSONStream(Isolate* isolate, JSONStream* stream) {
-    return old_space_.PrintHeapMapToJSONStream(isolate, stream);
+    old_space_.PrintHeapMapToJSONStream(isolate, stream);
   }
+#endif  // PRODUCT
 
   Isolate* isolate() const { return isolate_; }