use a hash table for the function cache as blink is leaking functiontemplates

test/cctest/test-api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 20020 matching lines @@
 THREADED_TEST(FunctionNew) {
   LocalContext env;
   v8::Isolate* isolate = env->GetIsolate();
   v8::HandleScope scope(isolate);
   Local<Object> data = v8::Object::New(isolate);
   function_new_expected_env = data;
   Local<Function> func = Function::New(isolate, FunctionNewCallback, data);
   env->Global()->Set(v8_str("func"), func);
   Local<Value> result = CompileRun("func();");
   CHECK(v8::Integer::New(isolate, 17)->Equals(result));
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   // Verify function not cached
-  int serial_number =
-      i::Smi::cast(v8::Utils::OpenHandle(*func)
-          ->shared()->get_api_func_data()->serial_number())->value();
-  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
-  i::Handle<i::FixedArray> cache(i_isolate->native_context()->function_cache());
-  if (serial_number < cache->length()) {
-    CHECK(cache->get(serial_number)->IsUndefined());
-  }
+  auto serial_number = handle(i::Smi::cast(v8::Utils::OpenHandle(*func)
+                                               ->shared()
+                                               ->get_api_func_data()
+                                               ->serial_number()),
+                              i_isolate);
+  auto cache = i_isolate->function_cache();
+  CHECK(cache->Lookup(serial_number)->IsTheHole());
   // Verify that each Function::New creates a new function instance
   Local<Object> data2 = v8::Object::New(isolate);
   function_new_expected_env = data2;
   Local<Function> func2 = Function::New(isolate, FunctionNewCallback, data2);
   CHECK(!func2->IsNull());
   CHECK(!func->Equals(func2));
   env->Global()->Set(v8_str("func2"), func2);
   Local<Value> result2 = CompileRun("func2();");
   CHECK(v8::Integer::New(isolate, 17)->Equals(result2));
 }
@@ skipping 1578 matching lines @@
   }
   {
     v8::TryCatch try_catch;
     uint16_t* data = reinterpret_cast<uint16_t*>(buffer);
     CHECK(v8::String::NewFromTwoByte(isolate, data, v8::String::kNormalString,
                                      length).IsEmpty());
     CHECK(try_catch.HasCaught());
   }
   free(buffer);
 }