Made Isolate a mandatory parameter for everything Handle-related.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 5e4390284c245bd3eb667158a8d0bb0d63d90f37..403f98ada96ff783148c612c3754ecb7913035a6 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -5571,7 +5571,7 @@ void Heap::ReportHeapStatistics(const char* title) {
   PrintF("old_gen_limit_factor_ %d\n", old_gen_limit_factor_);
 
   PrintF("\n");
-  PrintF("Number of handles : %d\n", HandleScope::NumberOfHandles());
+  PrintF("Number of handles : %d\n", HandleScope::NumberOfHandles(isolate_));
   isolate_->global_handles()->PrintStats();
   PrintF("\n");