Revert "Adding GCM support to the copresence component. The Copresence server can push directives (…

components/copresence/proto/data.proto

 syntax = "proto2";
 package copresence;
 option optimize_for = LITE_RUNTIME;
 import "enums.proto";
 import "identity.proto";
 message ClientVersion {
   optional string client = 1;
   optional string version_name = 2;
   optional int64 version_code = 3;
   optional string certificate_fingerprint = 4;
 }
 message Status {
   optional StatusCode code = 1;
   optional string message = 2;
 }
 message PushServiceRegistration {
   optional PushService service = 1;
-  optional GcmRegistration gcm_registration = 2;
-}
-message GcmRegistration {
-  optional string device_token = 1;
 }
 message DeviceIdentifiers {
   optional int32 ulr_device_id = 1;
   optional DeviceIdentity device_identity = 2;
   optional Identity registrant = 3;
 }
 message Token {
   message Debug {
     repeated string email = 2;
   }
@@ skipping 94 matching lines @@
 }
 message MessageResult {
   optional string published_message_id = 1;
 }
 message SubscriptionResult {
   optional string subscription_id = 1;
 }
 message OptInStateFilter {
   repeated OptInState allowed_opt_in_state = 1;
 }