update all embeds to non-experimental, unforked versions (#3269)

* update all embeds to non-experimental, unforked versions

* switch dartpad_picker back to dartpad.dev

* add jr staging to .firebaserc

.firebaserc

@@ -13,6 +13,7 @@
     "ft": "flutter-web-staging",
     "filip": "flutter-website-filiph-staging",
     "brianegan": "brianegan-flutter-staging",
-    "xster-staging": "flutter-website-staging-6f2ad"
+    "xster-staging": "flutter-website-staging-6f2ad",
+    "jr": "flutter-website-jr-staging"
   }
-}
+}

README.md

@@ -120,7 +120,7 @@ A typical DartPad example takes the form of an `iframe`, e.g. within a codelab's
 
 ```markdown
 <iframe
-  src="{{site.custom.dartpadx.embed-flutter-prefix}}?id=d7b09149ffee2f0535bb0c04d96987f5"
+  src="{{site.custom.dartpad.embed-flutter-prefix}}?id=d7b09149ffee2f0535bb0c04d96987f5"
   style="border: 1px solid lightgrey; margin-top: 10px; margin-bottom: 25px"
   frameborder="no" height="500" width="100%"
 ></iframe>

_config.yml

@@ -122,14 +122,9 @@ alert:
 custom:
   dartpad:
     embed-dart-prefix: https://dartpad.dev/embed-dart.html
+    embed-flutter-prefix: https://dartpad.dev/embed-flutter.html
     embed-html-prefix: https://dartpad.dev/embed-html.html
     embed-inline-prefix: https://dartpad.dev/embed-inline.html
-  dartpadx:
-    embed-dart-prefix: https://dartpad.dev/experimental/embed-new-dart.html
-    embed-flutter-prefix: https://unforked-dot-dart-pad.appspot.com/embed-flutter.html
-    embed-flutter-prefix-old: https://dartpad.dev/embed-flutter.html
-    embed-html-prefix: https://dartpad.dev/experimental/embed-new-html.html
-    embed-inline-prefix: https://dartpad.dev/experimental/embed-new-inline.html
 
   # callout_danger: '<div class="bs-callout bs-callout-danger">'
   # callout_default: '<div class="bs-callout bs-callout-default">'

src/_packages/dartpad_picker/lib/dartpad_picker.dart

@@ -20,7 +20,7 @@ class DartPadPicker {
   int _selected = 0;
 
   DartPadPicker(this.iFrameHost, this.selectElement, this.snippets,
-      {this.dartPadUrl = 'https://unforked-dot-dart-pad.appspot.com/'}) {
+      {this.dartPadUrl = 'https://dartpad.dev/'}) {
     _initSelectElement();
     _initDartPad();
   }