Use ScriptInterface::CreateObject for ToJSVal<CColor>, and for ToJSVal<Grid<u8> >, ToJSVal<Grid<u16> > used by the AIManager obtaining the pathfinder grid.

Make that function static, so that it can be used for these functions
without slowly having to obtain the ScriptInterface instance using
GetScriptInterfaceAndCBData just to get the JSContext again.
Remove few redundant conversions for CreateObject arguments.

Differential Revision: https://code.wildfiregames.com/D2128
Tested on: gcc 9.1.0, clang 8.0.1, Jenkins
Tedious performance testing in: D2128, D2127

This was SVN commit r22894.

source/ps/SavedGame.cpp

@@ -83,9 +83,10 @@ Status SavedGames::Save(const CStrW& name, const CStrW& description, CSimulation
 
 	JS::RootedValue metadata(cx);
 
-	simulation.GetScriptInterface().CreateObject(
+	ScriptInterface::CreateObject(
+		cx,
 		&metadata,
-		"engine_version", std::string(engine_version),
+		"engine_version", engine_version,
 		"time", static_cast<double>(now),
 		"playerID", g_Game->GetPlayerID(),
 		"mods", mods,
@@ -100,7 +101,8 @@ Status SavedGames::Save(const CStrW& name, const CStrW& description, CSimulation
 
 	JS::RootedValue cameraMetadata(cx);
 
-	simulation.GetScriptInterface().CreateObject(
+	ScriptInterface::CreateObject(
+		cx,
 		&cameraMetadata,
 		"PosX", cameraPosition.X,
 		"PosY", cameraPosition.Y,
@@ -232,7 +234,7 @@ JS::Value SavedGames::GetSavedGames(const ScriptInterface& scriptInterface)
 	JSAutoRequest rq(cx);
 
 	JS::RootedValue games(cx);
-	scriptInterface.CreateArray(&games);
+	ScriptInterface::CreateArray(cx, &games);
 
 	Status err;
 
@@ -268,7 +270,8 @@ JS::Value SavedGames::GetSavedGames(const ScriptInterface& scriptInterface)
 		JS::RootedValue metadata(cx, loader.GetMetadata());
 
 		JS::RootedValue game(cx);
-		scriptInterface.CreateObject(
+		ScriptInterface::CreateObject(
+			cx,
 			&game,
 			"id", pathnames[i].Basename(),
 			"metadata", metadata);