Print and save JS stacktrace on OOM crash.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 38968ad0b33b026b2a6087a908044a9026d8c009..ae9718e376269e026c163eeb1524fec98b943fbd 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -5366,6 +5366,11 @@ void Heap::RecordStats(HeapStats* stats, bool take_snapshot) {
   }
   if (stats->last_few_messages != NULL)
     GetFromRingBuffer(stats->last_few_messages);
+  if (stats->js_stacktrace != NULL) {
+    FixedStringAllocator fixed(stats->js_stacktrace, kStacktraceBufferSize - 1);
+    StringStream accumulator(&fixed);
+    isolate()->PrintStack(&accumulator, Isolate::kPrintStackVerbose);
+  }
 }