signin: Abort previous 'channelConnected' handling on retry

chrome/browser/resources/gaia_auth/main.js

Index: chrome/browser/resources/gaia_auth/main.js
diff --git a/chrome/browser/resources/gaia_auth/main.js b/chrome/browser/resources/gaia_auth/main.js
index e00869c9f52846661b26c448b50609244dade47d..1a59e0875b9439cb2b793bac11136d7094570428 100644
--- a/chrome/browser/resources/gaia_auth/main.js
+++ b/chrome/browser/resources/gaia_auth/main.js
@@ -224,6 +224,9 @@ Authenticator.prototype = {
 
     window.setTimeout(function() {
       if (!this.supportChannel_) {
+        // Give up previous channel and bind its 'channelConnected' to a no-op.
+        supportChannel.registerMessage('channelConnected', function() {});
+
         // Re-initialize the channel if it is not connected properly, e.g.
         // connect may be called before background script started running.
         this.initSupportChannel_();