[Web Payments] Add PopMany and Size functions to ViewStack

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 "ui/views/view.h"
 #include "ui/views/animation/bounds_animator.h"
 #include "ui/views/animation/bounds_animator_observer.h"
@@ skipping 15 matching lines @@
   // Adds a view to the stack and starts animating it in from the right. This
   // takes ownership of the view and calls set_owned_by_client() on it.
   // If |animate| is false, the view will simply be added to the hierarchy
   // without the sliding animation.
   void Push(std::unique_ptr<views::View> state, bool animate);
 
   // Removes a view from the stack, animates it out of view, and makes sure
   // it's properly deleted after the animation.
   void Pop();
 
+  // Removes |n| views from the stack but only animates the topmost one. The end
+  // 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;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(
       ViewStackTest, TestPopStateRemovesChildViewAndCleansUpState);
   FRIEND_TEST_ALL_PREFIXES(ViewStackTest, TestDeletingViewCleansUpState);
@@ skipping 17 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_