ChromeOS OOBE: Fix EULA Back button.

This Cl prevents duplicate "selected network connected" events
and fixes focus when returning to network selection dialog
after pressing "Back" button on EULA screen.

BUG=676774
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2700353002
Cr-Commit-Position: refs/heads/master@{#451979}
diff --git a/chrome/browser/resources/chromeos/login/oobe_dialog.js b/chrome/browser/resources/chromeos/login/oobe_dialog.js
index ab3be06..fc5ad21 100644
--- a/chrome/browser/resources/chromeos/login/oobe_dialog.js
+++ b/chrome/browser/resources/chromeos/login/oobe_dialog.js
@@ -24,7 +24,15 @@
     },
   },
 
-  focus: function() {},
+  focus: function() {
+    /* When Network Selection Dialog is shown because user pressed "Back"
+       button on EULA screen, display_manager does not inform this dialog that
+       it is shown. It ouly focuses this dialog.
+       So this emulates show().
+       TODO (alemate): fix this once event flow is updated.
+    */
+    this.show();
+  },
 
   /**
     * This is called from oobe_welcome when this dialog is shown.
diff --git a/chrome/browser/resources/chromeos/login/oobe_welcome.js b/chrome/browser/resources/chromeos/login/oobe_welcome.js
index 7cc3eb8..182ae14 100644
--- a/chrome/browser/resources/chromeos/login/oobe_welcome.js
+++ b/chrome/browser/resources/chromeos/login/oobe_welcome.js
@@ -296,6 +296,7 @@
    * @private
    */
   onSelectedNetworkConnected_: function() {
+    this.networkLastSelectedGuid_ = '';
     chrome.send('login.NetworkScreen.userActed', ['continue']);
   },