Implement the function.sent proposal.

src/runtime/runtime-generator.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/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/factory.h"
 #include "src/frames-inl.h"
 #include "src/objects-inl.h"
@@ skipping 159 matching lines @@
 // Returns receiver of generator activation.
 RUNTIME_FUNCTION(Runtime_GeneratorGetReceiver) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0);
 
   return generator->receiver();
 }
 
 
+// Returns input of generator activation.
+RUNTIME_FUNCTION(Runtime_GeneratorGetInput) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0);
+
+  return generator->input();
+}
+
+
 // Returns generator continuation as a PC offset, or the magic -1 or 0 values.
 RUNTIME_FUNCTION(Runtime_GeneratorGetContinuation) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0);
 
   return Smi::FromInt(generator->continuation());
 }
 
 
@@ skipping 21 matching lines @@
   return NULL;
 }
 
 
 RUNTIME_FUNCTION(Runtime_GeneratorThrow) {
   UNREACHABLE();  // Optimization disabled in SetUpGenerators().
   return NULL;
 }
 }  // namespace internal
 }  // namespace v8