Consolidate 4 GetIntentHelper functions

components/arc/intent_helper/arc_intent_helper_bridge.h

Index: components/arc/intent_helper/arc_intent_helper_bridge.h
diff --git a/components/arc/intent_helper/arc_intent_helper_bridge.h b/components/arc/intent_helper/arc_intent_helper_bridge.h
index c6bc2e792591f980f6400ed8db6540944a77e1d3..d8ad5213fc307463fd27e7f005b4bba5a202f8fd 100644
--- a/components/arc/intent_helper/arc_intent_helper_bridge.h
+++ b/components/arc/intent_helper/arc_intent_helper_bridge.h
@@ -37,6 +37,15 @@ class ArcIntentHelperBridge
       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,
@@ -67,6 +76,12 @@ class ArcIntentHelperBridge
   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_;