Settings/Oobe: Simplify cr-network-select and use flex

chrome/browser/resources/chromeos/login/oobe_welcome.js

Index: chrome/browser/resources/chromeos/login/oobe_welcome.js
diff --git a/chrome/browser/resources/chromeos/login/oobe_welcome.js b/chrome/browser/resources/chromeos/login/oobe_welcome.js
index 6fb51628056a970923924c724a9cebd46016125d..ef9a20081a53868bdf4ccbfa5dafd7c43da299df 100644
--- a/chrome/browser/resources/chromeos/login/oobe_welcome.js
+++ b/chrome/browser/resources/chromeos/login/oobe_welcome.js
@@ -72,6 +72,7 @@ Polymer({
     networkSelectionScreenShown: {
       type: Boolean,
       value: false,
+      observer: 'networkSelectionScreenShownChanged_',
     },
 
     /**
@@ -133,6 +134,15 @@ Polymer({
     this.$.welcomeNextButton.focus();
   },
 
+  /** @private */
+  networkSelectionScreenShownChanged_: function() {
+    if (this.networkSelectionScreenShown) {

[Alexander Alekseev, 2017/01/12 23:10:09]

Is this to fix "some of the network entries are not rendered after element was
shown until the 'refresh networks' event is triggered"?

This still looks like a bug in Polymer. Should we add a note on that here?

[stevenjb, 2017/01/13 00:03:14]

It's kind of a bug. The problem is, there is no DOM event to notify an element
when it is stamped. Since the element starts off hidden, we need to notify it
manually. It also makes sense to trigger a fresh network scan (e.g. in case the
user lingered on the first welcome screen), so this kills two birds with one
stone.

I added a comment.

+      this.async(function() {
+        this.$.networkSelect.refreshNetworks();
+      }.bind(this));
+    }
+  },
+
   /**
    * Handles "visible" event.
    * @private