fixing the autofill overlay problem (blue area for chrome) (flutter/engine#21610)

* fixing the autofill overlay problem (blue area for chrome)

* addression comments

engine/src/flutter/lib/web_ui/lib/src/engine/dom_renderer.dart

@@ -307,6 +307,21 @@ flt-glass-pane * {
 ''', sheet.cssRules.length);
     }
 
+    // This css prevents an autofill overlay brought by the browser during
+    // text field autofill by delaying the transition effect.
+    // See: https://github.com/flutter/flutter/issues/61132.
+    if(browserHasAutofillOverlay()) {
+        sheet.insertRule('''
+.transparentTextEditing:-webkit-autofill,
+.transparentTextEditing:-webkit-autofill:hover,
+.transparentTextEditing:-webkit-autofill:focus,
+.transparentTextEditing:-webkit-autofill:active {
+    -webkit-transition-delay: 99999s;
+}
+''', sheet.cssRules.length);
+    }
+
+
     final html.BodyElement bodyElement = html.document.body!;
     setElementStyle(bodyElement, 'position', 'fixed');
     setElementStyle(bodyElement, 'top', '0');

engine/src/flutter/lib/web_ui/lib/src/engine/text_editing/text_editing.dart

@@ -11,6 +11,16 @@ bool _debugVisibleTextEditing = false;
 /// The `keyCode` of the "Enter" key.
 const int _kReturnKeyCode = 13;
 
+/// Blink and Webkit engines, bring an overlay on top of the text field when it
+/// is autofilled.
+bool browserHasAutofillOverlay() =>
+    browserEngine == BrowserEngine.blink ||
+    browserEngine == BrowserEngine.webkit;
+
+/// `transparentTextEditing` class is configured to make the autofill overlay
+/// transparent.
+const String transparentTextEditingClass = 'transparentTextEditing';
+
 void _emptyCallback(dynamic _) {}
 
 /// These style attributes are constant throughout the life time of an input
@@ -39,7 +49,11 @@ void _setStaticStyleAttributes(html.HtmlElement domElement) {
     ..overflow = 'hidden'
     ..transformOrigin = '0 0 0';
 
-  /// This property makes the input's blinking cursor transparent.
+  if (browserHasAutofillOverlay()) {
+    domElement.classes.add(transparentTextEditingClass);
+  }
+
+  // This property makes the input's blinking cursor transparent.
   elementStyle.setProperty('caret-color', 'transparent');
 
   if (_debugVisibleTextEditing) {
@@ -80,6 +94,10 @@ void _hideAutofillElements(html.HtmlElement domElement,
       ..left = '-9999px';
   }
 
+  if (browserHasAutofillOverlay()) {
+    domElement.classes.add(transparentTextEditingClass);
+  }
+
   /// This property makes the input's blinking cursor transparent.
   elementStyle.setProperty('caret-color', 'transparent');
 }

engine/src/flutter/lib/web_ui/test/text_editing_test.dart

@@ -1343,6 +1343,18 @@ void testMain() {
         '500 12px sans-serif',
       );
 
+      // For `blink` and `webkit` browser engines the overlay would be hidden.
+      if (browserEngine == BrowserEngine.blink ||
+          browserEngine == BrowserEngine.webkit) {
+        expect(textEditing.editingElement.domElement.classes,
+            contains('transparentTextEditing'));
+      } else {
+        expect(
+            textEditing.editingElement.domElement.classes.any(
+                (element) => element.toString() == 'transparentTextEditing'),
+            isFalse);
+      }
+
       const MethodCall clearClient = MethodCall('TextInput.clearClient');
       sendFrameworkMessage(codec.encodeMethodCall(clearClient));
     },
@@ -1806,6 +1818,17 @@ void testMain() {
       final CssStyleDeclaration css = firstElement.style;
       expect(css.color, 'transparent');
       expect(css.backgroundColor, 'transparent');
+
+      // For `blink` and `webkit` browser engines the overlay would be hidden.
+      if (browserEngine == BrowserEngine.blink ||
+          browserEngine == BrowserEngine.webkit) {
+        expect(firstElement.classes, contains('transparentTextEditing'));
+      } else {
+        expect(
+            firstElement.classes.any(
+                (element) => element.toString() == 'transparentTextEditing'),
+            isFalse);
+      }
     });
 
     test('validate multi element form ids sorted for form id', () {