[Extensions Bindings] Add support for updateArgumentsPreValidate

extensions/renderer/api_binding_types.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef EXTENSIONS_RENDERER_API_BINDING_TYPES_H_
 #define EXTENSIONS_RENDERER_API_BINDING_TYPES_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/callback.h"
 #include "v8/include/v8.h"
 
 namespace extensions {
 namespace binding {
 
 // A callback to execute the given v8::Function with the provided context and
 // arguments.
 using RunJSFunction = base::Callback<void(v8::Local<v8::Function>,
                                           v8::Local<v8::Context>,
                                           int argc,
                                           v8::Local<v8::Value>[])>;
 
+// A callback to execute the given v8::Function synchronously and return the
+// result. Note that script can be suspended, so you need to be certain that
+// it is not before expected a synchronous result.
+using RunJSFunctionSync =
+    base::Callback<v8::Global<v8::Value>(v8::Local<v8::Function>,

[jbroman, 2017/01/02 19:46:38]

Mind a comment alluding to why this returns a Global<Value> rather than a
Local<Value> as would be usual? Ordinarily I'd expect that (using an
EscapableHandleScope), so this signature seems odd except for the way it's
implemented using WebLocalFrame's interface.

[Devlin, 2017/01/04 17:57:02]

Done.

+                                         v8::Local<v8::Context>,
+                                         int argc,
+                                         v8::Local<v8::Value>[])>;
+
 }  // namespace binding
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_API_BINDING_TYPES_H_