[WebPayments] Start populating the Payment Sheet.

chrome/browser/ui/views/payments/payment_request_views_util.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_PAYMENT_REQUEST_VIEWS_UTIL_H_
 #define CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_REQUEST_VIEWS_UTIL_H_
 
 #include <memory>
 
 #include "base/strings/string16.h"
 
 namespace views {
+class VectorIconButtonDelegate;
 class View;
 }
 
 namespace payments {
 
-// Creates a view to be displayed in the PaymentRequestDialog. |title| is the
-// text displayed on top of the dialog and |content_view| is displayed between
-// the title and the pay/cancel buttons. The returned view takes ownership of
-// |content_view|.
+enum class PaymentRequestCommonTags {
+  BACK_BUTTON_TAG = 0,
+  CLOSE_BUTTON_TAG,
+  // This is the max value of tags for controls common to multiple
+  // PaymentRequest contexts. Individual screens that handle both common and
+  // specific events with tags can start their specific tags at this value.
+  PAYMENT_REQUEST_COMMON_TAG_MAX
+};
+
+// Creates and returns a header for all the sheets in the PaymentRequest dialog.
+// The header contains an optional back arrow button (if |show_back_arrow| is
+// true), a |title| label, and a right-aligned X close button. |delegate|
+// becomes the delegate for the back and close buttons.
+// +---------------------------+
+// | <- | Title            | X |
+// +---------------------------+
+std::unique_ptr<views::View> CreateSheetHeaderView(
+    bool show_back_arrow,
+    const base::string16& title,
+    views::VectorIconButtonDelegate* delegate);
+
+// Creates a view to be displayed in the PaymentRequestDialog.
+// |header_view| is the view displayed on top of the dialog, containing title,
+// (optional) back button, and close buttons.
+// |content_view| is displayed between |header_view| and the pay/cancel buttons.
+// The returned view takes ownership of |header_view| and |content_view|.
+// +---------------------------+
+// |        HEADER VIEW        |
+// +---------------------------+
+// |          CONTENT          |
+// |           VIEW            |
+// +---------------------------+
+// |            | CANCEL | PAY |
+// +---------------------------+
 std::unique_ptr<views::View> CreatePaymentView(
-    const base::string16& title, std::unique_ptr<views::View> content_view);
+    std::unique_ptr<views::View> header_view,
+    std::unique_ptr<views::View> content_view);
 
 }  // namespace payments
 
 #endif  // CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_REQUEST_VIEWS_UTIL_H_