set offset to -9999px instead of -999

Author: nbayati

lib/web_ui/lib/src/engine/semantics/text_field.dart

@@ -402,7 +402,7 @@ class TextField extends RoleManager {
     }
 
     _initializeEditableElement();
-    activeEditableElement.style.transform = 'translate(-999px,-999px)';
+    activeEditableElement.style.transform = 'translate(${offScreenOffset}px, ${offScreenOffset}px)';
     _positionInputElementTimer?.cancel();
     _positionInputElementTimer = Timer(_delayBeforePlacement, () {
       editableElement?.style.transform = '';

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

@@ -34,6 +34,9 @@ bool _debugPrintTextInputCommands = false;
 /// The `keyCode` of the "Enter" key.
 const int _kReturnKeyCode = 13;
 
+/// Offset in pixels to place an element outside of the screen.
+const int offScreenOffset = -9999;
+
 /// Blink and Webkit engines, bring an overlay on top of the text field when it
 /// is autofilled.
 bool browserHasAutofillOverlay() =>
@@ -119,8 +122,8 @@ void _hideAutofillElements(DomHTMLElement domElement,
 
   if (isOffScreen) {
     elementStyle
-      ..top = '-9999px'
-      ..left = '-9999px';
+      ..top = '${offScreenOffset}px'
+      ..left = '${offScreenOffset}px';
   }
 
   if (browserHasAutofillOverlay()) {
@@ -1509,7 +1512,7 @@ class IOSTextEditingStrategy extends GloballyPositionedTextEditingStrategy {
     /// Position the element outside of the page before focusing on it. This is
     /// useful for not triggering a scroll when iOS virtual keyboard is
     /// coming up.
-    activeDomElement.style.transform = 'translate(-9999px, -9999px)';
+    activeDomElement.style.transform = 'translate(${offScreenOffset}px, ${offScreenOffset}px)';
 
     _canPosition = false;
   }

lib/web_ui/test/engine/semantics/text_field_test.dart

@@ -687,8 +687,9 @@ void testMain() {
         value: 'hello',
         isFocused: true,
         );
-      expect(strategy.activeDomElement.style.transform, 'translate(-999px, -999px)');
-      await Future<void>.delayed(const Duration(milliseconds: 201) , (){});
+      expect(strategy.activeDomElement.style.transform, 'translate(${offScreenOffset}px, ${offScreenOffset}px)');
+      // See [_delayBeforePlacement].
+      await Future<void>.delayed(const Duration(milliseconds: 120) , (){});
       expect(strategy.activeDomElement.style.transform, '');
     });