Simplify update error message support HTML.

chrome/browser/google/google_update_win.h

Index: chrome/browser/google/google_update_win.h
diff --git a/chrome/browser/google/google_update_win.h b/chrome/browser/google/google_update_win.h
index 0e02c76338509c39e8d1bc3a196d88a68c8b1491..a27e49ddc9ea421a1924a5cfe474f684bd0518a5 100644
--- a/chrome/browser/google/google_update_win.h
+++ b/chrome/browser/google/google_update_win.h
@@ -76,11 +76,13 @@ class UpdateCheckDelegate {
   virtual void OnUpgradeComplete(const base::string16& new_version) = 0;
 
   // Invoked following an unrecoverable error, indicated by |error_code|.
-  // |error_message|, if not empty, contains a localized string that may be
-  // presented to the user explaining the nature of the error. |new_version|, if
-  // not empty, indicates the version to which an upgrade attempt was made.
+  // |html_error_message|, if not empty, contains a localized string that may
+  // be presented to the user via html explaining the nature of the error; it
+  // should include the error code because that will not be displayed otherwise.

[grt (UTC plus 2), 2015/07/09 14:33:09]

Ideally, this comment should explain the contract for both implementors and
consumers. How about:

"|html_error_message|, if not empty, must be a localized string containing all
information required by users to act on the error as well as for support staff
to diagnose it (i.e., |error_code| and any other related state)."

[bcwhite, 2015/07/09 14:54:00]

Done.

+  // |new_version|, if not empty, indicates the version to which an upgrade
+  // attempt was made.
   virtual void OnError(GoogleUpdateErrorCode error_code,
-                       const base::string16& error_message,
+                       const base::string16& html_error_message,
                        const base::string16& new_version) = 0;
 
  protected: