Support switching multiple iframes

Author: tneotia

lib/src/replaced_element.dart

@@ -90,17 +90,13 @@ class ImageContentElement extends ReplacedElement {
   }
 }
 
-/// Create a webview controller and old src independent of [IframeContentElement]
-/// to make sure it doesn't reset when the html string is updated
-WebViewController controller;
-String oldUrl;
-
 /// [IframeContentElement is a [ReplacedElement] with web content.
 class IframeContentElement extends ReplacedElement {
   final String src;
   final double width;
   final double height;
   final NavigationDelegate navigationDelegate;
+  final GlobalKey key = GlobalKey();
 
   IframeContentElement({
     String name,
@@ -115,18 +111,12 @@ class IframeContentElement extends ReplacedElement {
   @override
   Widget toWidget(RenderContext context) {
     final sandboxMode = attributes["sandbox"];
-    if (oldUrl != null && src != oldUrl && controller != null) {
-      controller.loadUrl(src);
-    }
-    oldUrl = src;
     return Container(
       width: width ?? (height ?? 150) * 2,
       height: height ?? (width ?? 300) / 2,
       child: WebView(
         initialUrl: src,
-        onWebViewCreated: (WebViewController webController) {
-          controller = webController;
-        },
+        key: key,
         javascriptMode: sandboxMode == null || sandboxMode == "allow-scripts"
             ? JavascriptMode.unrestricted
             : JavascriptMode.disabled,