[esnext] prototype runtime implementation for async functions

src/bootstrapper.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/bootstrapper.h"
 
 #include "src/accessors.h"
 #include "src/api-natives.h"
 #include "src/code-stubs.h"
 #include "src/extensions/externalize-string-extension.h"
@@ skipping 2352 matching lines @@
     }
 
     Handle<AccessorInfo> script_is_embedder_debug_script =
         Accessors::ScriptIsEmbedderDebugScriptInfo(isolate, attribs);
     {
       AccessorConstantDescriptor d(
           Handle<Name>(Name::cast(script_is_embedder_debug_script->name())),
           script_is_embedder_debug_script, attribs);
       script_map->AppendDescriptor(&d);
     }
+
+    {
+      SimpleInstallFunction(container, "AsyncFunctionNext",
+                            Builtins::kAsyncFunctionNext, 2, false);
+      SimpleInstallFunction(container, "AsyncFunctionThrow",
+                            Builtins::kAsyncFunctionThrow, 2, false);
+    }
   }
 }
 
 
 void Bootstrapper::ExportExperimentalFromRuntime(Isolate* isolate,
                                                  Handle<JSObject> container) {
   HandleScope scope(isolate);
 
 #define INITIALIZE_FLAG(FLAG)                                         \
   {                                                                   \
@@ skipping 1263 matching lines @@
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   DCHECK(!IsActive());
 }
 
 }  // namespace internal
 }  // namespace v8