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

gin/arguments.cc

Index: gin/arguments.cc
diff --git a/gin/arguments.cc b/gin/arguments.cc
index 600a811f8483bb0fa77be9156c7c4578a5099167..4d01c0e44d9bce5b818b830f3499ccf6f4a07f96 100644
--- a/gin/arguments.cc
+++ b/gin/arguments.cc
@@ -32,6 +32,19 @@ v8::Local<v8::Value> Arguments::PeekNext() const {
   return (*info_)[next_];
 }
 
+std::vector<v8::Local<v8::Value>> Arguments::GetAll() const {
+  std::vector<v8::Local<v8::Value>> result;
+  int length = info_->Length();
+  if (length == 0)
+    return result;
+
+  result.reserve(length);
+  for (int i = 0; i < length; ++i)
+    result.push_back((*info_)[i]);
+
+  return result;
+}
+
 v8::Local<v8::Context> Arguments::GetHolderCreationContext() {
   return info_->Holder()->CreationContext();
 }