Support getting and deleting token for Instance ID.

google_apis/gcm/engine/registration_request.h

Index: google_apis/gcm/engine/registration_request.h
diff --git a/google_apis/gcm/engine/registration_request.h b/google_apis/gcm/engine/registration_request.h
index 1f707b9dd9ee276fd6ddb34609f8f4ddc9fb9595..2bc6f6e6c75b5fddbb5962d5229ecc90dc32f066 100644
--- a/google_apis/gcm/engine/registration_request.h
+++ b/google_apis/gcm/engine/registration_request.h
@@ -59,14 +59,12 @@ class GCM_EXPORT RegistrationRequest : public net::URLFetcherDelegate {
                               const std::string& registration_id)>
       RegistrationCallback;
 
-  // Details of the of the Registration Request. Only user's android ID and
-  // its serial number are optional and can be set to 0. All other parameters
-  // have to be specified to successfully complete the call.
+  // Encapsulates the common info about a registration/token request.

[Nicolas Zea, 2015/05/21 21:07:51]

Are all parameters mandatory?

[jianli, 2015/05/21 23:11:24]

Yes. Added to comment.

   struct GCM_EXPORT RequestInfo {
+   public:
     RequestInfo(uint64 android_id,
                 uint64 security_token,
-                const std::string& app_id,
-                const std::vector<std::string>& sender_ids);
+                const std::string& app_id);
     ~RequestInfo();
 
     // Android ID of the device.
@@ -75,10 +73,6 @@ class GCM_EXPORT RegistrationRequest : public net::URLFetcherDelegate {
     uint64 security_token;
     // Application ID.
     std::string app_id;
-    // Certificate of the application.
-    std::string cert;
-    // List of IDs of senders. Allowed up to 100.
-    std::vector<std::string> sender_ids;
   };
 
   RegistrationRequest(
@@ -96,6 +90,11 @@ class GCM_EXPORT RegistrationRequest : public net::URLFetcherDelegate {
   // URLFetcherDelegate implementation.
   void OnURLFetchComplete(const net::URLFetcher* source) override;
 
+  virtual void BuildRequestHeaders(std::string* extra_headers);

[Nicolas Zea, 2015/05/21 21:07:51]

Although I like the approach of injecting extra request headers that the request
consumes, I still think it would be cleaner to build the request such that you
don't need to overload these Build/Parse/Get methods and use a composition
approach instead.

How about just having callback plumbed in for the Build method here (it's always
called after the native build method I think), and having the source be a string
that's passed in at construction time? It doesn't need to be calculated
repeatedly right?

A similar approach could I think be taken for UnregistrationRequest.

[jianli, 2015/05/21 23:11:24]

I don't fully understand the callback proposal. Could you please illustrate
more?

[Nicolas Zea, 2015/05/22 14:53:13]

So there's be three new constructor parameters, two are callbacks
(build_body_callback, build_header_callback), and the other is a string
(source_for_recorder).

+  virtual void BuildRequestBody(std::string* body);
+  // Returns the source string to print by the stats recorder.
+  virtual std::string GetSourceForRecorder() const = 0;
+
  private:
   // Schedules a retry attempt, informs the backoff of a previous request's
   // failure, when |update_backoff| is true.