Add support for GCM subtypes to desktop Instance ID implementation

components/gcm_driver/gcm_client.h

Index: components/gcm_driver/gcm_client.h
diff --git a/components/gcm_driver/gcm_client.h b/components/gcm_driver/gcm_client.h
index add4deabf928426be6550db6b8c094db6c2195f6..3e399c561f8610b7f63375983040c5d4e790d87a 100644
--- a/components/gcm_driver/gcm_client.h
+++ b/components/gcm_driver/gcm_client.h
@@ -98,6 +98,7 @@ class GCMClient {
     ChromePlatform platform;
     ChromeChannel channel;
     std::string version;
+    std::string product_category_for_subtypes;

[jianli, 2016/08/08 22:11:51]

gcm_category

[johnme, 2016/08/10 13:09:55]

It's not just any category, it's specifically the category that represents the
product (a "package name" for Chrome itself), and should only be used when
requesting tokens where the app_id is sent as the subtype. Peter and I discussed
this at length before settling on the name product_category_for_subtypes, and I
think that's clearer than gcm_category, though perhaps there exists something
even clearer?

   };
 
   // Detailed information of the Send Error event.