ENGCOM-1456: [2.3-develop] [ForwardPort] Port of #12285 The option <var name='allowfullscreen'>false</var> for mobile device don't work in product view page gallery #15021

 - Merge Pull Request #15021 from gwharton/magento2:2.3-develop-12285
 - Merged commits:
   1. 435b165
   2. 4113f26
   3. c0b9e8f
   4. 05b1512
   5. 2701a4f

Author: magento-engcom-team

dev/tests/integration/testsuite/Magento/Framework/Config/ConverterTest.php

@@ -0,0 +1,86 @@
+<?php declare(strict_types=1);
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+namespace Magento\Framework\Config;
+
+/**
+ * Tests Magento\Framework\Config\Convert
+ */
+class ConverterTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * @var Converter
+     */
+    private $converter;
+
+    /**
+     * Tests config value "false" is not interpreted as true.
+     *
+     * @param string $sourceString
+     * @param array $expected
+     * @dataProvider parseVarElementDataProvider
+     */
+    public function testParseVarElement($sourceString, $expected)
+    {
+        $document = new \DOMDocument();
+        $document->loadXML($sourceString);
+        $actual = $this->converter->convert($document);
+
+        self::assertEquals(
+            $expected,
+            $actual
+        );
+    }
+
+    /**
+     * Data provider for testParseVarElement.
+     *
+     * @return array
+     */
+    public function parseVarElementDataProvider()
+    {
+        $sourceString = <<<'XML'
+<?xml version="1.0"?>
+<view xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
+xsi:noNamespaceSchemaLocation="urn:magento:framework:Config/etc/view.xsd">
+    <vars module="Magento_Test">    
+        <var name="str">some string</var>  
+        <var name="int-1">1</var>        
+        <var name="int-0">0</var>        
+        <var name="bool-true">true</var> 
+        <var name="bool-false">false</var> 
+    </vars>
+ </view>
+XML;
+        $expectedResult = [
+            'vars' => [
+                'Magento_Test' => [
+                    'str' => 'some string',
+                    'int-1' => '1',
+                    'int-0' => '0',
+                    'bool-true' => true,
+                    'bool-false' => false
+                ]
+            ]
+        ];
+
+        return [
+            [
+                $sourceString,
+                $expectedResult
+            ],
+        ];
+    }
+
+    /**
+     * @inheritdoc
+     */
+    protected function setUp()
+    {
+        $this->converter = \Magento\TestFramework\Helper\Bootstrap::getObjectManager()
+              ->create(\Magento\Framework\Config\Converter::class);
+    }
+}

lib/internal/Magento/Framework/Config/Converter.php

@@ -103,7 +103,9 @@ protected function parseVarElement(\DOMElement $node)
             }
         }
         if (!count($result)) {
-            $result = $node->nodeValue;
+            $result = (strtolower($node->nodeValue) !== 'true' && strtolower($node->nodeValue) !== 'false')
+                ? $node->nodeValue
+                : filter_var($node->nodeValue, FILTER_VALIDATE_BOOLEAN);
         }
         return $result;
     }