More doc

shell/platform/darwin/macos/framework/Source/FlutterEngine_Internal.h

@@ -96,6 +96,11 @@
 @end
 
 @interface FlutterEngine (TestMethods)
+/* Creates an accessibility bridge with the provided parameters.
+ *
+ * By default this method calls AccessibilityBridgeMac's initializer. Exposing
+ * this method allows unit tests to override in order to capture information.
+ */
 - (std::shared_ptr<flutter::AccessibilityBridgeMac>)
     createAccessibilityBridge:(nonnull FlutterEngine*)engine
                viewController:(nonnull FlutterViewController*)viewController;

shell/platform/windows/flutter_windows_engine.h

@@ -247,7 +247,8 @@ class FlutterWindowsEngine {
  protected:
   // Creates an accessibility bridge with the provided parameters.
   //
-  // This method allows unit tests to override in order to capture information.
+  // By default this method calls AccessibilityBridge's constructor. Exposing
+  // this method allows unit tests to override in order to capture information.
   virtual std::shared_ptr<AccessibilityBridge> CreateAccessibilityBridge(
       FlutterWindowsEngine* engine,
       FlutterWindowsView* view);