Scheme Registration - Only register custom scheme name one

Adding multiple entries to CefSettings.RegisterScheme that share the same scheme name
yet have different domain/schemehandlerfactory implementations is valid.

We will only register the first set of SchemeName/SchemeOption values (first call to RegisterScheme).

Author: amaitland

CefSharp.Core/Internals/CefSharpApp.h

@@ -91,6 +91,7 @@ namespace CefSharp
             {
                 String^ argument = "=";
                 bool hasCustomScheme = false;
+                auto registeredSchemes = gcnew List<String^>();
 
                 for each(CefCustomScheme^ scheme in _cefSettings->CefCustomSchemes)
                 {
@@ -101,8 +102,16 @@ namespace CefSharp
                         continue;
                     }
 
+                    //We've already registered this scheme name
+                    if (registeredSchemes->Contains(scheme->SchemeName))
+                    {
+                        continue;
+                    }
+
                     hasCustomScheme = true;
 
+                    registeredSchemes->Add(scheme->SchemeName);
+
                     argument += scheme->SchemeName + "|";
                     argument += ((int)scheme->Options).ToString() + ";";
                 }

CefSharp/DefaultApp.cs

@@ -27,6 +27,10 @@ void IApp.OnRegisterCustomSchemes(ISchemeRegistrar registrar)
 
         protected virtual void OnRegisterCustomSchemes(ISchemeRegistrar registrar)
         {
+            //Possible we have duplicate scheme names, we'll only register the first one
+            //Keep a list so we don't call AddCustomScheme twice for the same scheme name
+            var registeredSchemes = new List<string>();
+
             foreach (var scheme in Schemes)
             {
                 //We don't need to register http or https, they're built in schemes
@@ -35,9 +39,18 @@ protected virtual void OnRegisterCustomSchemes(ISchemeRegistrar registrar)
                     continue;
                 }
 
-                var success = registrar.AddCustomScheme(scheme.SchemeName, scheme.Options);
+                //We've already registered this scheme name
+                if (registeredSchemes.Contains(scheme.SchemeName))
+                {
+                    continue;
+                }
 
-                if (!success)
+                var success = registrar.AddCustomScheme(scheme.SchemeName, scheme.Options);
+                if (success)
+                {
+                    registeredSchemes.Add(scheme.SchemeName);
+                }
+                else
                 {
                     var msg = "CefSchemeRegistrar::AddCustomScheme failed for schemeName:" + scheme.SchemeName;
                     //TODO: Log error