[Web Payments] Implement proper focusing in Payment Request

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_VIEWS_PAYMENTS_VIEW_STACK_H_
 #define CHROME_BROWSER_UI_VIEWS_PAYMENTS_VIEW_STACK_H_
 
+#include <vector>
+
 #include "ui/views/view.h"
 #include "ui/views/animation/bounds_animator.h"
 #include "ui/views/animation/bounds_animator_observer.h"
 
 namespace payments {
 class PaymentRequestBrowserTestBase;
 }  // namespace payments
 
 // This view represents a stack of views that slide in over one another from
 // left to right. It manages the animation and lifetime of views that are
@@ skipping 19 matching lines @@
   // result is an animation from the top-most view to the destination view.
   void PopMany(int n);
 
   size_t size() const;
 
   // views::View:
   // The children of this view must not be able to process events when the views
   // are being animated so this returns false when an animation is in progress.
   bool CanProcessEventsWithinSubtree() const override;
   void Layout() override;
+  void RequestFocus() override;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(
       ViewStackTest, TestPopStateRemovesChildViewAndCleansUpState);
   FRIEND_TEST_ALL_PREFIXES(ViewStackTest, TestDeletingViewCleansUpState);
   FRIEND_TEST_ALL_PREFIXES(ViewStackTest, TestInitialStateAddedAsChildView);
   FRIEND_TEST_ALL_PREFIXES(ViewStackTest, TestPushStateAddsViewToChildren);
   FRIEND_TEST_ALL_PREFIXES(ViewStackTest, TestLayoutUpdatesAnimations);
   friend class ViewStackTest;
   friend class payments::PaymentRequestBrowserTestBase;
@@ skipping 12 matching lines @@
   std::unique_ptr<views::BoundsAnimator> slide_out_animator_;
 
   // Should be the last member, because views need to be destroyed before other
   // members, and members are destroyed in reverse order of their creation.
   std::vector<std::unique_ptr<views::View>> stack_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewStack);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_PAYMENTS_VIEW_STACK_H_