Skip the SAML confirm password screen when a single password is scraped

chrome/browser/resources/gaia_auth_host/authenticator.js

Index: chrome/browser/resources/gaia_auth_host/authenticator.js
diff --git a/chrome/browser/resources/gaia_auth_host/authenticator.js b/chrome/browser/resources/gaia_auth_host/authenticator.js
index 4159df30217fb4a29688f9a6a3651a135242e753..f73eb7c690e1ddead228daeb27f3a92eff8e581f 100644
--- a/chrome/browser/resources/gaia_auth_host/authenticator.js
+++ b/chrome/browser/resources/gaia_auth_host/authenticator.js
@@ -650,6 +650,14 @@ cr.define('cr.login', function() {
       // password when it is available but not a mandatory requirement.
       console.warn('Authenticator: No password scraped for SAML.');
     } else if (this.needPassword) {
+      if (this.samlHandler_.scrapedPasswordCount == 1) {
+        // If we scraped exactly one password, we verify that it and complete
+        // the authentication right away.
+        var passwords = this.samlHandler_.getConsolidatedScrapedPasswords_();
+        this.verifyConfirmedPassword(passwords[0]);

[xiyuan, 2016/05/04 19:35:04]

getConsolidatedScrapedPasswords_ is private and we should not call it. And
calling verifyConfirmedPassword is unnecessary. Let's just get the password and
finish the flow here.

Add a getter to saml handler, e.g.
  get firstScrapedPassword() {
    var scraped = this.getConsolidatedScrapedPasswords_();
    return scraped.length ? scraped[0] : '';
  }

then we just get that and finish the flow here:
  this.password_ = this.samlHandler_.firstScrapedPassword();
  this.onAuthCompleted_();

[afakhry, 2016/05/04 20:16:15]

Done.

+        return;
+      }
+
       if (this.confirmPasswordCallback) {
         // Confirm scraped password. The flow follows in
         // verifyConfirmedPassword.