Added support for multiple parameters to Extension API callbacks.

chrome/browser/extensions/extension_function.cc

Index: chrome/browser/extensions/extension_function.cc
diff --git a/chrome/browser/extensions/extension_function.cc b/chrome/browser/extensions/extension_function.cc
index d8ab5b994accbd8505b2f17b721afa744015a458..9caad98e40fb8faa1e04c2a351710aed0563fa0a 100644
--- a/chrome/browser/extensions/extension_function.cc
+++ b/chrome/browser/extensions/extension_function.cc
@@ -93,8 +93,13 @@ void ExtensionFunction::SetArgs(const base::ListValue* args) {
   args_.reset(args->DeepCopy());
 }
 
-const Value* ExtensionFunction::GetResultValue() {
-  return result_.get();
+void ExtensionFunction::SetResult(base::Value* result) {
+  results_.reset(new base::ListValue());
+  results_->Append(result);
+}
+
+const ListValue* ExtensionFunction::GetResultList() {
+  return results_.get();
 }
 
 const std::string ExtensionFunction::GetError() {
@@ -129,14 +134,12 @@ void ExtensionFunction::SendResponseImpl(base::ProcessHandle process,
     return;
   }
 
-  // Value objects can't be directly serialized in our IPC code, so we wrap the
-  // result_ Value with a ListValue (also transferring ownership of result_).
-  base::ListValue result_wrapper;
-  if (result_.get())
-    result_wrapper.Append(result_.release());
+  // If results were never set, we send an empty argument list.
+  if (!results_.get())
+    results_.reset(new ListValue());
 
   ipc_sender->Send(new ExtensionMsg_Response(
-      routing_id, request_id_, success, result_wrapper, GetError()));
+      routing_id, request_id_, success, *results_.release(), GetError()));

[koz (OOO until 15th September), 2012/07/13 04:48:16]

Is this a memory leak?

I think a better way to do it would be to have results_ just be a ListValue, not
a scoped_ptr<ListValue>. In SetResult() you can Clear() it, rather than
allocating a new one.

[Matt Tytel, 2012/07/13 05:14:39]

:( Yes that is.

As for the scoped_ptr business, the json schema compiler will (soon) return a
new ListValue for the arguments so it will be useful just to .reset() to that
Value.

[not at google - send to devlin, 2012/07/13 05:20:05]

In the JSC case it's also reasonable to do

void SetResults(scoped_ptr<ListValue> results) {
  results_.Swap(results.get());
}

or whatever equivalent compiles.

 }
 
 void ExtensionFunction::HandleBadMessage(base::ProcessHandle process) {