[breadcrumb] Add a getToolTipButtons service

Add getToolTipButtons() service that returns every breadcrumb <button>
that has attribute [has-tooltip].

Bug: 1035691
Change-Id: I719b7ea301f127ba14efc92e5e7a7b34174c04b6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2141559
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Alex Danilo <adanilo@chromium.org>
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Auto-Submit: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#757710}

ui/file_manager/file_manager/foreground/js/ui/breadcrumb.js

@@ -339,6 +339,18 @@ class BreadCrumb extends HTMLElement {
     });
   }
 
+  /**
+   * Returns breadcrumb buttons that have a 'has-tooltip' attribute. Note the
+   * elider button is excluded since it has an i18n aria-label.
+   *
+   * @return {!Array<HTMLButtonElement>} buttons Caller could remove the tool
+   *    tip event listeners from the returned buttons.
+   */
+  getToolTipButtons() {
+    const hasToolTip = 'button:not([elider])[has-tooltip]';
+    return Array.from(this.shadowRoot.querySelectorAll(hasToolTip));
+  }
+
   /**
    * Handles 'click' events.
    *