Minor, fix the PagedForm UIExample

Summary: A couple of features got added when this was used in Diffusion, but
didn't get backported to the UIExample.

See: <https://github.com/facebook/phabricator/issues/454>

Auditors: btrahan

src/applications/uiexample/examples/PhabricatorPagedFormExample.php

@@ -18,24 +18,28 @@ final class PhabricatorPagedFormExample extends PhabricatorUIExample {
 
 
     $page1 = id(new PHUIFormPageView())
+      ->setPageName(pht('Page 1'))
       ->addControl(
         id(new AphrontFormTextControl())
           ->setName('page1')
           ->setLabel('Page 1'));
 
     $page2 = id(new PHUIFormPageView())
+      ->setPageName(pht('Page 2'))
       ->addControl(
         id(new AphrontFormTextControl())
           ->setName('page2')
           ->setLabel('Page 2'));
 
     $page3 = id(new PHUIFormPageView())
+      ->setPageName(pht('Page 3'))
       ->addControl(
         id(new AphrontFormTextControl())
           ->setName('page3')
           ->setLabel('Page 3'));
 
     $page4 = id(new PHUIFormPageView())
+      ->setPageName(pht('Page 4'))
       ->addControl(
         id(new AphrontFormTextControl())
           ->setName('page4')

src/view/form/PHUIFormPageView.php

@@ -191,7 +191,9 @@ class PHUIFormPageView extends AphrontView {
 
   public function readFromObject($object) {
     foreach ($this->getControls() as $name => $control) {
-      $control->readValueFromDictionary($object);
+      if (is_array($object)) {
+        $control->readValueFromDictionary($object);
+      }
     }
 
     return $this;

src/view/form/PHUIPagedFormView.php

@@ -266,16 +266,17 @@ final class PHUIPagedFormView extends AphrontTagView {
       $errors = id(new AphrontErrorView())->setErrors($errors);
     }
 
-    $header = null;
+    $box = id(new PHUIObjectBoxView())
+      ->setFormError($errors)
+      ->setForm($form);
+
     if ($selected_page->getPageName()) {
       $header = id(new PHUIHeaderView())
         ->setHeader($selected_page->getPageName());
+      $box->setHeader($header);
     }
 
-    return id(new PHUIObjectBoxView())
-      ->setHeader($header)
-      ->setFormError($errors)
-      ->setForm($form);
+    return $box;
   }
 
 }