Add various UMA histograms for measuring GCM crypto performance

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 5a24c4d597e00aedaf90dbf31f79ac1564cc864e..4b216842a7eb10d054706889fadf15373c0d489e 100644
--- a/components/gcm_driver/gcm_client.h
+++ b/components/gcm_driver/gcm_client.h
@@ -269,10 +269,10 @@ class GCMClient {
                     const std::string& receiver_id,
                     const OutgoingMessage& message) = 0;
 
-  // Records a decryption failure due to |reason| for the |app_id|.
+  // Records a decryption failure due to |result| for the |app_id|.
   virtual void RecordDecryptionFailure(
       const std::string& app_id,
-      GCMEncryptionProvider::DecryptionFailure reason) = 0;
+      GCMEncryptionProvider::DecryptionResult result) = 0;
 
   // Enables or disables internal activity recording.
   virtual void SetRecording(bool recording) = 0;