[Interpreter] Add Ignition statistics JavaScript extension.

src/d8.cc

Index: src/d8.cc
diff --git a/src/d8.cc b/src/d8.cc
index 169bc263934a8f1344419ac53ee0d88b8431d50f..287c6a0f7a00f98c3c63f7942a9013ad30ea2626 100644
--- a/src/d8.cc
+++ b/src/d8.cc
@@ -19,6 +19,7 @@
 
 #ifndef V8_SHARED
 #include <algorithm>
+#include <fstream>
 #include <vector>
 #endif  // !V8_SHARED
 
@@ -1276,6 +1277,21 @@ struct CounterAndKey {
 inline bool operator<(const CounterAndKey& lhs, const CounterAndKey& rhs) {
   return strcmp(lhs.key, rhs.key) < 0;
 }
+
+void Shell::WriteIgnitionDispatchCountersFile(v8::Isolate* isolate) {
+  HandleScope handle_scope(isolate);
+  Local<Context> context = Context::New(isolate);
+  Context::Scope context_scope(context);
+
+  Local<Object> dispatch_counters = reinterpret_cast<i::Isolate*>(isolate)
+                                        ->interpreter()
+                                        ->GetDispatchCountersObject();
+  std::ofstream dispatch_counters_stream(
+      i::FLAG_trace_ignition_dispatches_output_file);
+  dispatch_counters_stream << *String::Utf8Value(
+      JSON::Stringify(context, dispatch_counters).ToLocalChecked());
+}
+
 #endif  // !V8_SHARED
 
 
@@ -1314,12 +1330,6 @@ void Shell::OnExit(v8::Isolate* isolate) {
     delete [] counters;
   }
 
-  if (i::FLAG_trace_ignition_dispatches) {
-    reinterpret_cast<i::Isolate*>(isolate)
-        ->interpreter()
-        ->WriteDispatchCounters();
-  }
-
   delete counters_file_;
   delete counter_map_;
 #endif  // !V8_SHARED
@@ -2484,6 +2494,12 @@ int Shell::Main(int argc, char* argv[]) {
       RunShell(isolate);
     }
 
+#ifndef V8_SHARED
+    if (i::FLAG_ignition && i::FLAG_trace_ignition_dispatches) {
+      WriteIgnitionDispatchCountersFile(isolate);
+    }
+#endif
+
     // Shut down contexts and collect garbage.
     evaluation_context_.Reset();
 #ifndef V8_SHARED