Implement PageTypes Enum

Summary: Split page_types into an array of single items

Test Plan: NP

Author: Luca Bruno

src/FacebookAds/Object/Values/PageTypes.php

@@ -0,0 +1,41 @@
+<?php
+/**
+ * Copyright 2014 Facebook, Inc.
+ *
+ * You are hereby granted a non-exclusive, worldwide, royalty-free license to
+ * use, copy, modify, and distribute this software in source code or binary
+ * form for use in connection with the web services and APIs provided by
+ * Facebook.
+ *
+ * As with any software that integrates with the Facebook platform, your use
+ * of this software is subject to the Facebook Developer Principles and
+ * Policies [http://developers.facebook.com/policy/]. This copyright notice
+ * shall be included in all copies or substantial portions of the software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+namespace FacebookAds\Object\Values;
+
+use FacebookAds\Enum\AbstractEnum;
+
+/**
+ * @method static PageTypes getInstance()
+ */
+class PageTypes extends AbstractEnum {
+
+  const DESKTOP_FEED = 'desktopfeed';
+  const HOME = 'home';
+  const LEGACY_EXTERNAL = 'legacyexternal';
+  const LOGOUT = 'logout';
+  const MOBILE_EXTERNAL = 'mobileexternal';
+  const MOBILE_FEED = 'mobilefeed';
+  const RIGHT_COLUMN = 'rightcolumn';
+}

test/FacebookAdsTest/Object/ReachFrequencyPredictionTest.php

@@ -29,6 +29,7 @@
 use FacebookAds\Object\Fields\ReachFrequencyPredictionFields as RF;
 use FacebookAds\Object\TargetingSpecs;
 use FacebookAds\Object\Values\AdObjectives;
+use FacebookAds\Object\Values\PageTypes;
 use FacebookAdsTest\Config\SkippableFeatureTestInterface;
 
 class ReachFrequencyPredictionTest extends AbstractCrudObjectTestCase
@@ -52,8 +53,9 @@ public function testCrudAccess() {
     $targeting->{TargetingSpecsFields::AGE_MAX} = 35;
     $targeting->{TargetingSpecsFields::AGE_MIN} = 20;
     $targeting->{TargetingSpecsFields::GENDERS} = array(2);
-    $targeting->{TargetingSpecsFields::PAGE_TYPES} = array('desktopfeed');
-
+    $targeting->{TargetingSpecsFields::PAGE_TYPES} = array(
+      PageTypes::DESKTOP_FEED,
+    );
 
     $prediction->setData(array(
       RF::BUDGET => 3000000,