Add a fake cursor (blinking UIView) to the widget extension.

ios/chrome/widget_extension/widget_view_controller.mm

Index: ios/chrome/widget_extension/widget_view_controller.mm
diff --git a/ios/chrome/widget_extension/widget_view_controller.mm b/ios/chrome/widget_extension/widget_view_controller.mm
index dfe050a6a5c0766cc0e7d3564151b35788ff1729..735d49e34ec6f410364d6d22b104c6f805712cd9 100644
--- a/ios/chrome/widget_extension/widget_view_controller.mm
+++ b/ios/chrome/widget_extension/widget_view_controller.mm
@@ -30,6 +30,18 @@
   WidgetView* widgetView = [[WidgetView alloc] init];
   self.widgetView = widgetView;
   [self.view addSubview:self.widgetView];
+
+  [self.widgetView setTranslatesAutoresizingMaskIntoConstraints:NO];
+  [NSLayoutConstraint activateConstraints:@[
+    [self.widgetView.leadingAnchor
+        constraintEqualToAnchor:[self.view leadingAnchor]],
+    [self.widgetView.trailingAnchor
+        constraintEqualToAnchor:[self.view trailingAnchor]],
+    [self.widgetView.heightAnchor
+        constraintEqualToAnchor:[self.view heightAnchor]],
+    [self.widgetView.widthAnchor
+        constraintEqualToAnchor:[self.view widthAnchor]]
+  ]];
 }
 
 @end