The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1c0dd493fa569a4b6fd4ef13784acd3bebeedc6a

commit 1c0dd493fa569a4b6fd4ef13784acd3bebeedc6a
Author: Bailey Berro <baileyberro@chromium.org>
Date: Tue Sep 11 00:27:19 2018

Initialize mountUrl_ in Add Share Dialog so it is not undefined

- After switching to cr-searchable-drop-down, mountUrl_ was undefined, this
switches it to being explicitly initialized to an empty string so the Add
button is correctly disabled.

Bug:  chromium:882590 
Change-Id: I38dcc3a17b9406f2d633b90154114ad20876fa91
Reviewed-on: https://chromium-review.googlesource.com/1217514
Commit-Queue: Bailey Berro <baileyberro@chromium.org>
Reviewed-by: Scott Chen <scottchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590128}
[modify] https://crrev.com/1c0dd493fa569a4b6fd4ef13784acd3bebeedc6a/chrome/browser/resources/settings/downloads_page/add_smb_share_dialog.js

 Issue 882797  has been merged into this issue.

Can you please mark which OS's this is impacting?

Sorry- this is a CrOS issue

Your change meets the bar and is auto-approved for M70. Please go ahead and merge the CL to branch 3538 manually. Please contact milestone owner if you have questions.
Owners: benmason@(Android), kariahda@(iOS), geohsu@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d0b8a22c6563c820bf19cba1568e88a28ed54ff0

commit d0b8a22c6563c820bf19cba1568e88a28ed54ff0
Author: Bailey Berro <baileyberro@chromium.org>
Date: Wed Sep 12 13:13:01 2018

Initialize mountUrl_ in Add Share Dialog so it is not undefined

- After switching to cr-searchable-drop-down, mountUrl_ was undefined, this
switches it to being explicitly initialized to an empty string so the Add
button is correctly disabled.

Bug:  chromium:882590 
Change-Id: I38dcc3a17b9406f2d633b90154114ad20876fa91
Reviewed-on: https://chromium-review.googlesource.com/1217514
Commit-Queue: Bailey Berro <baileyberro@chromium.org>
Reviewed-by: Scott Chen <scottchen@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#590128}(cherry picked from commit 1c0dd493fa569a4b6fd4ef13784acd3bebeedc6a)
Reviewed-on: https://chromium-review.googlesource.com/1221470
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Cr-Commit-Position: refs/branch-heads/3538@{#326}
Cr-Branched-From: 79f7c91a2b2a2932cd447fa6f865cb6662fa8fa6-refs/heads/master@{#587811}
[modify] https://crrev.com/d0b8a22c6563c820bf19cba1568e88a28ed54ff0/chrome/browser/resources/settings/downloads_page/add_smb_share_dialog.js

Verified fixed, the Add button is disabled when mount URL is empty (see attached screenshot).

Chrome OS: 11021.27.0
Chrome: 70.0.3538.32
Device: Santa

Deleted: Screenshot 2018-09-25 at 2.05.32 PM.png 96.1 KB

	Screenshot 2018-09-25 at 2.05.32 PM.png 96.1 KB View Download