Add implementations for onShare and onSearchWeb (#2143)

Fixes #2088

## Pre-launch Checklist

- [x] I read the [Flutter Style Guide] _recently_, and have followed its
advice.
- [x] I signed the [CLA].
- [x] I read the [Contributors Guide].
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] All existing and new tests are passing.

---------

Co-authored-by: Brett Morgan <brett.morgan@gmail.com>

simplistic_editor/lib/basic_text_field.dart

@@ -28,6 +28,8 @@ class BasicTextField extends StatefulWidget {
     VoidCallback? onSelectAll,
     VoidCallback? onLookUp,
     VoidCallback? onLiveTextInput,
+    VoidCallback? onSearchWeb,
+    VoidCallback? onShare,
     TextSelectionToolbarAnchors anchors,
   ) {
     return AdaptiveTextSelectionToolbar.editable(
@@ -38,10 +40,9 @@ class BasicTextField extends StatefulWidget {
       onSelectAll: onSelectAll,
       onLookUp: onLookUp,
       onLiveTextInput: onLiveTextInput,
+      onSearchWeb: onSearchWeb,
+      onShare: onShare,
       anchors: anchors,
-      // TODO(Renzo-Olivares): https://github.com/flutter/samples/issues/2088
-      onSearchWeb: null,
-      onShare: null,
     );
   }
 

simplistic_editor/lib/basic_text_input_client.dart

@@ -26,6 +26,8 @@ typedef BasicTextFieldContextMenuBuilder = Widget Function(
   VoidCallback? onSelectAll,
   VoidCallback? onLookUp,
   VoidCallback? onLiveTextInput,
+  VoidCallback? onSearchWeb,
+  VoidCallback? onShare,
   TextSelectionToolbarAnchors anchors,
 );
 
@@ -867,6 +869,13 @@ class BasicTextInputClientState extends State<BasicTextInputClient>
                 liveTextInputEnabled
                     ? () => _startLiveTextInput(SelectionChangedCause.toolbar)
                     : null,
+                searchWebEnabled
+                    ? () =>
+                        _searchWebForSelection(SelectionChangedCause.toolbar)
+                    : null,
+                shareEnabled
+                    ? () => _shareSelection(SelectionChangedCause.toolbar)
+                    : null,
                 _contextMenuAnchors,
               );
             },
@@ -1016,6 +1025,65 @@ class BasicTextInputClientState extends State<BasicTextInputClient>
     );
   }
 
+  @override
+  bool get searchWebEnabled {
+    if (defaultTargetPlatform != TargetPlatform.iOS) {
+      return false;
+    }
+
+    return !textEditingValue.selection.isCollapsed &&
+        textEditingValue.selection.textInside(textEditingValue.text).trim() !=
+            '';
+  }
+
+  /// Launch a web search on the current selection,
+  /// as in the "Search Web" edit menu button on iOS.
+  ///
+  /// Currently this is only implemented for iOS.
+  Future<void> _searchWebForSelection(SelectionChangedCause cause) async {
+    final String text =
+        textEditingValue.selection.textInside(textEditingValue.text);
+    if (text.isNotEmpty) {
+      await SystemChannels.platform.invokeMethod(
+        'SearchWeb.invoke',
+        text,
+      );
+    }
+  }
+
+  @override
+  bool get shareEnabled {
+    switch (defaultTargetPlatform) {
+      case TargetPlatform.android:
+      case TargetPlatform.iOS:
+        return !textEditingValue.selection.isCollapsed &&
+            textEditingValue.selection
+                    .textInside(textEditingValue.text)
+                    .trim() !=
+                '';
+      case TargetPlatform.macOS:
+      case TargetPlatform.fuchsia:
+      case TargetPlatform.linux:
+      case TargetPlatform.windows:
+        return false;
+    }
+  }
+
+  /// Launch the share interface for the current selection,
+  /// as in the "Share..." edit menu button on iOS.
+  ///
+  /// Currently this is only implemented for iOS and Android.
+  Future<void> _shareSelection(SelectionChangedCause cause) async {
+    final String text =
+        textEditingValue.selection.textInside(textEditingValue.text);
+    if (text.isNotEmpty) {
+      await SystemChannels.platform.invokeMethod(
+        'Share.invoke',
+        text,
+      );
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     return Actions(