Print Preview: Do not expand settings at startup

In Polymer 2, shouldExpandSettings_ is called when the computed property
shouldShowMoreSettings_ is undefined, and returns true in this case,
resulting in a flash of the expanded settings. Return false unless
shouldShowMoreSettings_ is set to the boolean value of false.

Bug: 898100
Change-Id: I7154772921c59ba24ba1c80901da4b962305eeac
Reviewed-on: https://chromium-review.googlesource.com/c/1297605Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602494}

chrome/browser/resources/print_preview/new/app.js

@@ -635,6 +635,11 @@ Polymer({
    * @private
    */
   shouldExpandSettings_: function() {
+    if (this.settingsExpandedByUser_ === undefined ||
+        this.shouldShowMoreSettings_ === undefined) {
+      return false;
+    }
+
     // Expand the settings if the user has requested them expanded or if more
     // settings is not displayed (i.e. less than 6 total settings available).
     return this.settingsExpandedByUser_ || !this.shouldShowMoreSettings_;