Fix SSO credential error reporting in file share dialog.

Set SSO credential error as general error instead of credential error,
which displays error under username/password and is invisible in SSO.

Reset error state after changing authentication method.

Bug: 1038896
Change-Id: I27fcd9b3eb4e045f2e37de9c76ae932a59b7305c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1978687
Commit-Queue: Tomasz Dobrowolski <tomdobro@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Anand Mistry <amistry@chromium.org>
Auto-Submit: Tomasz Dobrowolski <tomdobro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733940}

ui/webui/resources/cr_components/chromeos/smb_shares/add_smb_share_dialog.js

@@ -106,6 +106,7 @@ Polymer({
             SmbAuthMethod.KERBEROS :
             SmbAuthMethod.CREDENTIALS;
       },
+      observer: 'onAuthenticationMethodChanged_',
     },
 
     /** @private */
@@ -172,6 +173,15 @@ Polymer({
     this.mountName_ = parts[parts.length - 1];
   },
 
+  /**
+   * @param {string} newValue
+   * @param {string} oldValue
+   * @private
+   */
+  onAuthenticationMethodChanged_(newValue, oldValue) {
+    this.resetErrorState_();
+  },
+
   /**
    * @return {boolean}
    * @private
@@ -223,8 +233,13 @@ Polymer({
     switch (result) {
       // Credential Error
       case SmbMountResult.AUTHENTICATION_FAILED:
-        this.setCredentialError_(
-            loadTimeData.getString('smbShareAddedAuthFailedMessage'));
+        if (this.authenticationMethod_ === SmbAuthMethod.KERBEROS) {
+          this.setGeneralError_(
+              loadTimeData.getString('smbShareAddedAuthFailedMessage'));
+        } else {
+          this.setCredentialError_(
+              loadTimeData.getString('smbShareAddedAuthFailedMessage'));
+        }
         break;
 
       // Path Errors