Improve error messages for push API subscribe failure.

The "no sender id provided" error message is displayed in two main
situations:
- When no GCM sender ID has been provided in the manifest
- When the manifest is not found or empty

This commit introduces a new error message for the latter case
("manifest empty or missing") and updates the former message to
better reflect the actual error ("gcm_sender_id not found in manifest").

BUG=463113

Review URL: https://codereview.chromium.org/1506373002

Cr-Commit-Position: refs/heads/master@{#365396}

1 files changed, 5 insertions, 1 deletions

diff --git a/content/public/common/push_messaging_status.h b/content/public/common/push_messaging_status.h
index 191c28e..2fd887f 100644
--- a/content/public/common/push_messaging_status.h
+++ b/content/public/common/push_messaging_status.h
@@ -52,13 +52,17 @@ enum PushRegistrationStatus {
   // Registration failed because the public key could not be retrieved.
   PUSH_REGISTRATION_STATUS_PUBLIC_KEY_UNAVAILABLE = 11,
 
+  // Registration failed because the manifest could not be retrieved or was
+  // empty.
+  PUSH_REGISTRATION_STATUS_MANIFEST_EMPTY_OR_MISSING = 12,
+
   // NOTE: Do not renumber these as that would confuse interpretation of
   // previously logged data. When making changes, also update the enum list
   // in tools/metrics/histograms/histograms.xml to keep it in sync, and
   // update PUSH_REGISTRATION_STATUS_LAST below.
 
   PUSH_REGISTRATION_STATUS_LAST =
-      PUSH_REGISTRATION_STATUS_PUBLIC_KEY_UNAVAILABLE
+      PUSH_REGISTRATION_STATUS_MANIFEST_EMPTY_OR_MISSING
 };
 
 // Push unregistration success/error codes for internal use & reporting in UMA.