Add support for GCM subtypes to desktop Instance ID implementation

google_apis/gcm/engine/registration_request.h

 // Copyright 2014 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 GOOGLE_APIS_GCM_ENGINE_REGISTRATION_REQUEST_H_
 #define GOOGLE_APIS_GCM_ENGINE_REGISTRATION_REQUEST_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 49 matching lines @@
   // Callback completing the registration request.
   typedef base::Callback<void(Status status,
                               const std::string& registration_id)>
       RegistrationCallback;
 
   // Defines the common info about a registration/token request. All parameters
   // are mandatory.
   struct GCM_EXPORT RequestInfo {
     RequestInfo(uint64_t android_id,
                 uint64_t security_token,
-                const std::string& app_id);
+                const std::string& category,
+                const std::string& subtype);
     ~RequestInfo();
 
     // Android ID of the device.
     uint64_t android_id;
     // Security token of the device.
     uint64_t security_token;
-    // Application ID.
-    std::string app_id;
+
+    // Application ID used in Chrome to refer to registration/token's owner.
+    const std::string& app_id() { return subtype.empty() ? category : subtype; }

[jianli, 2016/08/17 21:12:08]

nit: add const modifier

[johnme, 2016/08/18 17:43:22]

Done.

+
+    // GCM category field derived from the |app_id|.

[jianli, 2016/08/17 21:12:08]

Having "derived from the |app_id|" in this comment and next comment are
confusing. Probably you can remove both.

[johnme, 2016/08/18 17:43:22]

Done.

+    std::string category;
+    // GCM subtype field derived from the |app_id|.
+    std::string subtype;
   };
 
   // Encapsulates the custom logic that is needed to build and process the
   // registration request.
   class GCM_EXPORT CustomRequestHandler {
    public:
     CustomRequestHandler();
     virtual ~CustomRequestHandler();
 
     // Builds the HTTP request body data. It is called after
@@ skipping 51 matching lines @@
   std::string source_to_record_;
 
   base::WeakPtrFactory<RegistrationRequest> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RegistrationRequest);
 };
 
 }  // namespace gcm
 
 #endif  // GOOGLE_APIS_GCM_ENGINE_REGISTRATION_REQUEST_H_