Consolidate 4 GetIntentHelper functions

components/arc/intent_helper/arc_intent_helper_bridge.h

 // 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.
 
 #ifndef COMPONENTS_ARC_INTENT_HELPER_ARC_INTENT_HELPER_BRIDGE_H_
 #define COMPONENTS_ARC_INTENT_HELPER_ARC_INTENT_HELPER_BRIDGE_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 19 matching lines @@
 class LocalActivityResolver;
 class SetWallpaperDelegate;
 
 // Receives intents from ARC.
 class ArcIntentHelperBridge
     : public ArcService,
       public InstanceHolder<mojom::IntentHelperInstance>::Observer,
       public mojom::IntentHelperHost,
       public ash::LinkHandlerModelFactory {
  public:
+  enum class GetResult {
+    // Failed. The intent_helper instance is not yet ready. This is a temporary
+    // error.
+    FAILED_ARC_NOT_READY,
+    // Failed. Either ARC is not supported at all or intent_helper instance
+    // version is too old.
+    FAILED_ARC_NOT_SUPPORTED,
+  };
+
   ArcIntentHelperBridge(
       ArcBridgeService* bridge_service,
       const scoped_refptr<ActivityIconLoader>& icon_loader,
       const scoped_refptr<LocalActivityResolver>& activity_resolver);
   ~ArcIntentHelperBridge() override;
 
   // InstanceHolder<mojom::IntentHelperInstance>::Observer
   void OnInstanceReady() override;
   void OnInstanceClosed() override;
 
@@ skipping 10 matching lines @@
   std::unique_ptr<ash::LinkHandlerModel> CreateModel(const GURL& url) override;
 
   // Returns false if |package_name| is for the intent_helper apk.
   static bool IsIntentHelperPackage(const std::string& package_name);
 
   // Filters out handlers that belong to the intent_helper apk and returns
   // a new array.
   static mojo::Array<mojom::UrlHandlerInfoPtr> FilterOutIntentHelper(
       mojo::Array<mojom::UrlHandlerInfoPtr> handlers);
 
+  // Gets the mojo instance if it's available. On failure, returns nullptr and
+  // updates |out_error_code| if it's not nullptr.
+  static mojom::IntentHelperInstance* GetIntentHelperInstance(

[Luis Héctor Chávez, 2016/09/14 20:28:49]

I wonder if it's better to provide two versions of this function to avoid having
to pass the magic nullptr as second parameter. Of course the second version will
just pass nullptr to the first one :P

[Yusuke Sato, 2016/09/14 21:02:25]

I didn't do this as function overloading is discouraged (to some extent) in
Chromium, but well, in this case having two versions is probably okay. Done.

[Luis Héctor Chávez, 2016/09/14 21:09:12]

You can add a "WithErrorCode" suffix if you want to avoid overloading and make
the intention clearer. Up to you.

[Yusuke Sato, 2016/09/14 21:21:49]

Done.

+      int min_instance_version,
+      GetResult* out_error_code);
+
  private:
   mojo::Binding<mojom::IntentHelperHost> binding_;
   scoped_refptr<ActivityIconLoader> icon_loader_;
   scoped_refptr<LocalActivityResolver> activity_resolver_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcIntentHelperBridge);
 };
 
 }  // namespace arc
 
 #endif  // COMPONENTS_ARC_INTENT_HELPER_ARC_INTENT_HELPER_BRIDGE_H_