[Web Payments] Implement proper focusing in Payment Request

chrome/browser/ui/views/payments/view_stack.cc

Index: chrome/browser/ui/views/payments/view_stack.cc
diff --git a/chrome/browser/ui/views/payments/view_stack.cc b/chrome/browser/ui/views/payments/view_stack.cc
index 78f44ef73b87bea26d3d059054f024f29581085d..ac77c98e386461a3549f80965666fc9e2c2803d4 100644
--- a/chrome/browser/ui/views/payments/view_stack.cc
+++ b/chrome/browser/ui/views/payments/view_stack.cc
@@ -49,6 +49,7 @@ void ViewStack::Push(std::unique_ptr<views::View> view, bool animate) {
   // Add the new view to the stack so it can be popped later when navigating
   // back to the previous screen.
   stack_.push_back(std::move(view));
+  RequestFocus();
 }
 
 void ViewStack::Pop() {
@@ -95,6 +96,14 @@ void ViewStack::Layout() {
   UpdateAnimatorBounds(slide_out_animator_.get(), out_new_destination);
 }
 
+void ViewStack::RequestFocus() {
+  // The view can only be focused if it has a widget already. It's possible that
+  // this isn't the case if some views are pushed before the stack is added to a
+  // hierarchy that has a widget.
+  if (top()->GetWidget())
+    top()->RequestFocus();
+}
+
 void ViewStack::UpdateAnimatorBounds(
     views::BoundsAnimator* animator, const gfx::Rect& target) {
   // If an animator is currently animating, figure out which views and update
@@ -115,4 +124,5 @@ void ViewStack::OnBoundsAnimatorDone(views::BoundsAnimator* animator) {
 
   stack_.pop_back();
   DCHECK(!stack_.empty()) << "State stack should never be empty";
+  RequestFocus();
 }