[webview_flutter] Revert addition of onUrlChanged (#4524)

Reverts https://github.com/flutter/plugins/pull/4509, which is ecosystem-breaking since it adds a new method to the interface that no existing code implements.

Note that while this PR is technically a breaking change, it is deliberately versioned as a non-breaking change so that people will automatically pick up the fix for the previous accidentally-breaking change. (In practice, this revert would only breaking if someone implemented this new method in an unendorsed webview implementation sometime in the last ~12 hours that the change was live).
diff --git a/packages/webview_flutter/webview_flutter_platform_interface/CHANGELOG.md b/packages/webview_flutter/webview_flutter_platform_interface/CHANGELOG.md
index 212f1c4..efc43cf 100644
--- a/packages/webview_flutter/webview_flutter_platform_interface/CHANGELOG.md
+++ b/packages/webview_flutter/webview_flutter_platform_interface/CHANGELOG.md
@@ -1,3 +1,8 @@
+## 1.5.1
+
+* Reverts the addition of `onUrlChanged`, which was unintentionally a breaking
+  change.
+
 ## 1.5.0
 
 * Added `onUrlChanged` callback to platform callback handler.
@@ -20,4 +25,4 @@
 
 ## 1.0.0
 
-* Extracted platform interface from `webview_flutter`.
\ No newline at end of file
+* Extracted platform interface from `webview_flutter`.
diff --git a/packages/webview_flutter/webview_flutter_platform_interface/lib/src/method_channel/webview_method_channel.dart b/packages/webview_flutter/webview_flutter_platform_interface/lib/src/method_channel/webview_method_channel.dart
index 3a6047d..8df9f4c 100644
--- a/packages/webview_flutter/webview_flutter_platform_interface/lib/src/method_channel/webview_method_channel.dart
+++ b/packages/webview_flutter/webview_flutter_platform_interface/lib/src/method_channel/webview_method_channel.dart
@@ -53,9 +53,6 @@
       case 'onPageStarted':
         _platformCallbacksHandler.onPageStarted(call.arguments['url']!);
         return null;
-      case 'onUrlChanged':
-        _platformCallbacksHandler.onUrlChanged(call.arguments['url']!);
-        return null;
       case 'onWebResourceError':
         _platformCallbacksHandler.onWebResourceError(
           WebResourceError(
diff --git a/packages/webview_flutter/webview_flutter_platform_interface/lib/src/platform_interface/webview_platform_callbacks_handler.dart b/packages/webview_flutter/webview_flutter_platform_interface/lib/src/platform_interface/webview_platform_callbacks_handler.dart
index eb97f5b..44dae2e 100644
--- a/packages/webview_flutter/webview_flutter_platform_interface/lib/src/platform_interface/webview_platform_callbacks_handler.dart
+++ b/packages/webview_flutter/webview_flutter_platform_interface/lib/src/platform_interface/webview_platform_callbacks_handler.dart
@@ -24,16 +24,9 @@
   void onPageFinished(String url);
 
   /// Invoked by [WebViewPlatformController] when a page is loading.
-  /// Only works when [WebSettings.hasProgressTracking] is set to `true`.
+  /// /// Only works when [WebSettings.hasProgressTracking] is set to `true`.
   void onProgress(int progress);
 
-  /// Invoked by [WebViewPlatformController] when the webview's URL has changed.
-  ///
-  /// Unlike [onPageStarted], [onProgress], and [onPageFinished],
-  /// [onUrlChanged] also fires when navigating without a full page load
-  /// e.g. when navigating within a single page application.
-  void onUrlChanged(String url);
-
   /// Report web resource loading error to the host application.
   void onWebResourceError(WebResourceError error);
 }
diff --git a/packages/webview_flutter/webview_flutter_platform_interface/pubspec.yaml b/packages/webview_flutter/webview_flutter_platform_interface/pubspec.yaml
index 57ae9a0..33eb77c 100644
--- a/packages/webview_flutter/webview_flutter_platform_interface/pubspec.yaml
+++ b/packages/webview_flutter/webview_flutter_platform_interface/pubspec.yaml
@@ -4,7 +4,7 @@
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview_flutter%22
 # NOTE: We strongly prefer non-breaking changes, even at the expense of a
 # less-clean API. See https://flutter.dev/go/platform-interface-breaking-changes
-version: 1.5.0
+version: 1.5.1
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
@@ -19,4 +19,4 @@
   flutter_test:
     sdk: flutter
   mockito: ^5.0.0
-  pedantic: ^1.10.0
\ No newline at end of file
+  pedantic: ^1.10.0
diff --git a/packages/webview_flutter/webview_flutter_platform_interface/test/src/method_channel/webview_method_channel_test.dart b/packages/webview_flutter/webview_flutter_platform_interface/test/src/method_channel/webview_method_channel_test.dart
index f827d8f..3960135 100644
--- a/packages/webview_flutter/webview_flutter_platform_interface/test/src/method_channel/webview_method_channel_test.dart
+++ b/packages/webview_flutter/webview_flutter_platform_interface/test/src/method_channel/webview_method_channel_test.dart
@@ -13,9 +13,7 @@
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
-  group(
-      'Tests on `plugin.flutter.io/webview_<channel_id>` channel dart->native',
-      () {
+  group('Tests on `plugin.flutter.io/webview_<channel_id>` channel', () {
     const int channelId = 1;
     const MethodChannel channel =
         MethodChannel('plugins.flutter.io/webview_$channelId');
@@ -556,40 +554,6 @@
     });
   });
 
-  group(
-      'Tests on `plugin.flutter.io/webview_<channel_id>` channel native->dart',
-      () {
-    const int channelId = 1;
-    final WebViewPlatformCallbacksHandler callbacksHandler =
-        MockWebViewPlatformCallbacksHandler();
-    final JavascriptChannelRegistry javascriptChannelRegistry =
-        MockJavascriptChannelRegistry();
-
-    MethodChannelWebViewPlatform(
-      channelId,
-      callbacksHandler,
-      javascriptChannelRegistry,
-    );
-
-    tearDown(() {
-      reset(callbacksHandler);
-    });
-
-    test('onUrlChanged', () async {
-      // Run
-      await ServicesBinding.instance!.defaultBinaryMessenger
-          .handlePlatformMessage(
-        'plugins.flutter.io/webview_$channelId',
-        StandardMethodCodec()
-            .encodeMethodCall(MethodCall('onUrlChanged', {'url': 'Test Url'})),
-        null,
-      );
-
-      // Verify
-      verify(callbacksHandler.onUrlChanged('Test Url'));
-    });
-  });
-
   group('Tests on `plugins.flutter.io/cookie_manager` channel', () {
     const MethodChannel cookieChannel =
         MethodChannel('plugins.flutter.io/cookie_manager');