[WebPayments] Implement state transitions in desktop WebPayments dialog.

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

Index: chrome/browser/ui/views/payments/view_stack_state.cc
diff --git a/chrome/browser/ui/views/payments/view_stack_state.cc b/chrome/browser/ui/views/payments/view_stack_state.cc
new file mode 100644
index 0000000000000000000000000000000000000000..9359d35db28229daa4a58fbdab0f741356dec39d
--- /dev/null
+++ b/chrome/browser/ui/views/payments/view_stack_state.cc
@@ -0,0 +1,20 @@
+// 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.
+
+#include "chrome/browser/ui/views/payments/view_stack_state.h"
+
+#include "ui/views/view.h"
+
+ViewStackState::ViewStackState() {}
+
+ViewStackState::~ViewStackState() {}
+
+views::View* ViewStackState::GetView() {
+  if (!view_) {
+    view_.reset(CreateView());
+    view_->set_owned_by_client();
+  }
+
+  return view_.get();
+}