[flutter] Update ViewportMetrics construction to use new API.

TEST: Bots on //c/integration/+/76357
Change-Id: I15662e567db3085e5b992f91d8cd2550fe8222b7
diff --git a/runtime/flutter_runner/platform_view.cc b/runtime/flutter_runner/platform_view.cc
index 3724642..702f05c 100644
--- a/runtime/flutter_runner/platform_view.cc
+++ b/runtime/flutter_runner/platform_view.cc
@@ -231,24 +231,20 @@
 
 void PlatformView::FlushViewportMetrics() {
   const auto scale = metrics_.scale;
-  blink::ViewportMetrics metrics = {
-      .device_pixel_ratio = scale,
 
-      .physical_width = metrics_.size.width * scale,
-      .physical_height = metrics_.size.height * scale,
-
-      .physical_padding_top = metrics_.padding.top * scale,
-      .physical_padding_right = metrics_.padding.right * scale,
-      .physical_padding_bottom = metrics_.padding.bottom * scale,
-      .physical_padding_left = metrics_.padding.left * scale,
-
-      .physical_view_inset_top = metrics_.view_inset.top * scale,
-      .physical_view_inset_right = metrics_.view_inset.right * scale,
-      .physical_view_inset_bottom = metrics_.view_inset.bottom * scale,
-      .physical_view_inset_left = metrics_.view_inset.left * scale,
-  };
-
-  SetViewportMetrics(metrics);
+  SetViewportMetrics({
+      scale,                               // device_pixel_ratio
+      metrics_.size.width * scale,         // physical_width
+      metrics_.size.height * scale,        // physical_height
+      metrics_.padding.top * scale,        // physical_padding_top
+      metrics_.padding.right * scale,      // physical_padding_right
+      metrics_.padding.bottom * scale,     // physical_padding_bottom
+      metrics_.padding.left * scale,       // physical_padding_left
+      metrics_.view_inset.top * scale,     // physical_view_inset_top
+      metrics_.view_inset.right * scale,   // physical_view_inset_right
+      metrics_.view_inset.bottom * scale,  // physical_view_inset_bottom
+      metrics_.view_inset.left * scale     // physical_view_inset_left
+  });
 }
 
 // |fuchsia::ui::input::InputMethodEditorClient|