Push API: rename registration to subscription.

public/platform/WebPushSubscription.h

Index: public/platform/WebPushSubscription.h
diff --git a/public/platform/WebPushRegistration.h b/public/platform/WebPushSubscription.h
similarity index 52%
copy from public/platform/WebPushRegistration.h
copy to public/platform/WebPushSubscription.h
index 18b6ce1e08fd6f7b366ac4b98e8bd0e45c585134..51528a3951624c98d3b26f1a523da0b45f208983 100644
--- a/public/platform/WebPushRegistration.h
+++ b/public/platform/WebPushSubscription.h
@@ -2,24 +2,24 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef WebPushRegistration_h
-#define WebPushRegistration_h
+#ifndef WebPushSubscription_h
+#define WebPushSubscription_h
 
 #include "WebString.h"
 
 namespace blink {
 
-struct WebPushRegistration {
-    WebPushRegistration(const WebString& endpoint, const WebString& registrationId)
+struct WebPushSubscription {
+    WebPushSubscription(const WebString& endpoint, const WebString& subscriptionId)
         : endpoint(endpoint)
-        , registrationId(registrationId)
+        , subscriptionId(subscriptionId)
     {
     }
 
     WebString endpoint;
-    WebString registrationId;
+    WebString subscriptionId;
 };
 
 } // namespace blink
 
-#endif // WebPushRegistration_h
+#endif // WebPushSubscription_h