[Reland][gin] Add Arguments::GetAll()

extensions/renderer/event_emitter.cc

 // 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.
 
 #include "extensions/renderer/event_emitter.h"
 
 #include <algorithm>
 
 #include "extensions/renderer/api_event_listeners.h"
 #include "gin/object_template_builder.h"
@@ skipping 112 matching lines @@
 
 void EventEmitter::Dispatch(gin::Arguments* arguments) {
   if (!valid_)
     return;
 
   if (listeners_->GetNumListeners() == 0)
     return;
   v8::HandleScope handle_scope(arguments->isolate());
   v8::Local<v8::Context> context =
       arguments->isolate()->GetCurrentContext();
-  std::vector<v8::Local<v8::Value>> v8_args;
-  if (arguments->Length() > 0) {
-    // Converting to v8::Values should never fail.
-    CHECK(arguments->GetRemaining(&v8_args));
-  }
+  std::vector<v8::Local<v8::Value>> v8_args = arguments->GetAll();
   Fire(context, &v8_args, nullptr);
 }
 
 }  // namespace extensions