Make _embedBuilder default

app/lib/pages/home_page.dart

@@ -3,9 +3,7 @@ import 'dart:convert';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_quill/models/documents/document.dart';
-import 'package:flutter_quill/models/documents/nodes/leaf.dart' as leaf;
 import 'package:flutter_quill/widgets/controller.dart';
-import 'package:flutter_quill/widgets/default_styles.dart';
 import 'package:flutter_quill/widgets/editor.dart';
 import 'package:flutter_quill/widgets/toolbar.dart';
 
@@ -77,7 +75,6 @@ class _HomePageState extends State<HomePage> {
               focusNode: _focusNode,
               autoFocus: true,
               readOnly: false,
-              embedBuilder: _embedBuilder,
               enableInteractiveSelection: true,
               expands: false,
               padding: EdgeInsets.zero,
@@ -87,21 +84,4 @@ class _HomePageState extends State<HomePage> {
       ],
     );
   }
-
-  Widget _embedBuilder(BuildContext context, leaf.Embed node) {
-    switch (node.value.type) {
-      case 'hr':
-        final style = QuillStyles.getStyles(context, true);
-        return Divider(
-          height: style.paragraph.style.fontSize * style.paragraph.style.height,
-          thickness: 2,
-          color: Colors.grey.shade200,
-        );
-      default:
-        throw UnimplementedError(
-            'Embeddable type "${node.value.type}" is not supported by default embed '
-            'builder of QuillEditor. You must pass your own builder function to '
-            'embedBuilder property of QuillEditor or QuillField widgets.');
-    }
-  }
 }

lib/widgets/editor.dart

@@ -19,6 +19,7 @@ import 'package:flutter_quill/widgets/text_selection.dart';
 import 'box.dart';
 import 'controller.dart';
 import 'cursor.dart';
+import 'default_styles.dart';
 import 'delegate.dart';
 
 abstract class EditorState extends State<RawEditor> {
@@ -66,6 +67,23 @@ abstract class RenderAbstractEditor {
   void selectPosition(SelectionChangedCause cause);
 }
 
+Widget _defaultEmbedBuilder(BuildContext context, Embed node) {
+  switch (node.value.type) {
+    case 'hr':
+      final style = QuillStyles.getStyles(context, true);
+      return Divider(
+        height: style.paragraph.style.fontSize * style.paragraph.style.height,
+        thickness: 2,
+        color: Colors.grey.shade200,
+      );
+    default:
+      throw UnimplementedError(
+          'Embeddable type "${node.value.type}" is not supported by default embed '
+          'builder of QuillEditor. You must pass your own builder function to '
+          'embedBuilder property of QuillEditor or QuillField widgets.');
+  }
+}
+
 class QuillEditor extends StatefulWidget {
   final QuillController controller;
   final FocusNode focusNode;
@@ -102,7 +120,7 @@ class QuillEditor extends StatefulWidget {
       this.keyboardAppearance = Brightness.light,
       this.scrollPhysics,
       this.onLaunchUrl,
-      @required this.embedBuilder})
+      this.embedBuilder = _defaultEmbedBuilder})
       : assert(controller != null),
         assert(scrollController != null),
         assert(scrollable != null),