Support loading arbitrary files instead of only Flutter assets

Author: mvanbeusekom

packages/webview_flutter/webview_flutter_platform_interface/lib/src/method_channel/webview_method_channel.dart

@@ -80,9 +80,9 @@ class MethodChannelWebViewPlatform implements WebViewPlatformController {
   }
 
   @override
-  Future<void> loadFlutterAsset(String assetName) async {
-    assert(assetName != null);
-    return _channel.invokeMethod<void>('loadFlutterAsset', assetName);
+  Future<void> loadFile(String absoluteFilePath) async {
+    assert(absoluteFilePath != null);
+    return _channel.invokeMethod<void>('loadFile', absoluteFilePath);
   }
 
   @override

packages/webview_flutter/webview_flutter_platform_interface/lib/src/platform_interface/webview_platform_controller.dart

@@ -23,12 +23,11 @@ abstract class WebViewPlatformController {
   /// The `handler` parameter must not be null.
   WebViewPlatformController(WebViewPlatformCallbacksHandler handler);
 
-  /// Loads the Flutter asset specified in the pubspec.yaml file.
+  /// Loads the file located on the specified [absoluteFilePath].
   ///
-  /// Throws an ArgumentError if [assetName] is not part of the specified assets
-  /// in the pubspec.yaml file.
-  Future<void> loadFlutterAsset(
-    String assetName,
+  /// Throws an ArgumentError if the [absoluteFilePath] does not exist.
+  Future<void> loadFile(
+    String absoluteFilePath,
   ) {
     throw UnimplementedError(
         "WebView loadFlutterAsset is not implemented on the current platform");

packages/webview_flutter/webview_flutter_platform_interface/test/src/method_channel/webview_method_channel_test.dart

@@ -55,17 +55,17 @@ void main() {
       log.clear();
     });
 
-    test('loadFlutterAsset', () async {
-      await webViewPlatform.loadFlutterAsset(
-        'folder/asset.html',
+    test('loadFile', () async {
+      await webViewPlatform.loadFile(
+        '/folder/asset.html',
       );
 
       expect(
         log,
         <Matcher>[
           isMethodCall(
-            'loadFlutterAsset',
-            arguments: 'folder/asset.html',
+            'loadFile',
+            arguments: '/folder/asset.html',
           ),
         ],
       );