Update V8 to r6101 as required by WebKit r74534

Change-Id: I7f84af8dd732f11898fd644b2c2b1538914cb78d
diff --git a/src/counters.h b/src/counters.h
index aed46cf..048fdaa 100644
--- a/src/counters.h
+++ b/src/counters.h
@@ -28,6 +28,9 @@
 #ifndef V8_COUNTERS_H_
 #define V8_COUNTERS_H_
 
+#include "../include/v8.h"
+#include "allocation.h"
+
 namespace v8 {
 namespace internal {