[web] Fix incorrect physical size due to visualviewport api on iOS

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

@@ -480,11 +480,11 @@ flt-glass-pane * {
     setElementAttribute(_sceneHostElement!, 'aria-hidden', 'true');
 
     if (html.window.visualViewport == null && isWebKit) {
-      // Safari sometimes gives us bogus innerWidth/innerHeight values when the
-      // page loads. When it changes the values to correct ones it does not
-      // notify of the change via `onResize`. As a workaround, we set up a
-      // temporary periodic timer that polls innerWidth and triggers the
-      // resizeListener so that the framework can react to the change.
+      // Older Safari versions sometimes give us bogus innerWidth/innerHeight
+      // values when the page loads. When it changes the values to correct ones
+      // it does not notify of the change via `onResize`. As a workaround, we
+      // set up a temporary periodic timer that polls innerWidth and triggers
+      // the resizeListener so that the framework can react to the change.
       //
       // Safari 13 has implemented visualViewport API so it doesn't need this
       // timer.
@@ -606,12 +606,12 @@ flt-glass-pane * {
   void _metricsDidChange(html.Event? event) {
     updateSemanticsScreenProperties();
     if (isMobile && !window.isRotation() && textEditing.isEditing) {
-      window.computeOnScreenKeyboardInsets();
+      window.computeOnScreenKeyboardInsets(true);
       EnginePlatformDispatcher.instance.invokeOnMetricsChanged();
     } else {
       window._computePhysicalSize();
       // When physical size changes this value has to be recalculated.
-      window.computeOnScreenKeyboardInsets();
+      window.computeOnScreenKeyboardInsets(false);
       EnginePlatformDispatcher.instance.invokeOnMetricsChanged();
     }
   }

lib/web_ui/lib/src/engine/window.dart

@@ -181,9 +181,25 @@ class EngineFlutterWindow extends ui.SingletonFlutterWindow {
       double windowInnerWidth;
       double windowInnerHeight;
       final html.VisualViewport? viewport = html.window.visualViewport;
+
       if (viewport != null) {
-        windowInnerWidth = viewport.width!.toDouble() * devicePixelRatio;
-        windowInnerHeight = viewport.height!.toDouble() * devicePixelRatio;
+        if (operatingSystem == OperatingSystem.iOs) {
+          /// Chrome on iOS reports incorrect viewport.height when app
+          /// starts in portrait orientation and the phone is rotated to
+          /// landscape.
+          ///
+          /// We instead use documentElement clientWidth/Height to read
+          /// accurate physical size. VisualViewport api is only used during
+          /// text editing to make sure inset is correctly reported to
+          /// framework.
+          final double docWidth = html.document.documentElement!.clientWidth.toDouble();
+          final double docHeight = html.document.documentElement!.clientHeight.toDouble();
+          windowInnerWidth = docWidth * devicePixelRatio;
+          windowInnerHeight = docHeight * devicePixelRatio;
+        } else {
+          windowInnerWidth = viewport.width!.toDouble() * devicePixelRatio;
+          windowInnerHeight = viewport.height!.toDouble() * devicePixelRatio;
+        }
       } else {
         windowInnerWidth = html.window.innerWidth! * devicePixelRatio;
         windowInnerHeight = html.window.innerHeight! * devicePixelRatio;
@@ -195,11 +211,15 @@ class EngineFlutterWindow extends ui.SingletonFlutterWindow {
     }
   }
 
-  void computeOnScreenKeyboardInsets() {
+  void computeOnScreenKeyboardInsets(bool isEditingOnMobile) {
     double windowInnerHeight;
     final html.VisualViewport? viewport = html.window.visualViewport;
     if (viewport != null) {
-      windowInnerHeight = viewport.height!.toDouble() * devicePixelRatio;
+      if (operatingSystem == OperatingSystem.iOs && !isEditingOnMobile) {
+        windowInnerHeight = html.document.documentElement!.clientHeight * devicePixelRatio;
+      } else {
+        windowInnerHeight = viewport.height!.toDouble() * devicePixelRatio;
+      }
     } else {
       windowInnerHeight = html.window.innerHeight! * devicePixelRatio;
     }