[WebPayments] Factor out sheet-specific logic in Controllers.

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

+// 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/payment_request_views_util.h"
+
+#include "base/strings/utf_string_conversions.h"
+#include "ui/views/background.h"
+#include "ui/views/controls/button/md_text_button.h"
+#include "ui/views/controls/label.h"
+#include "ui/views/layout/fill_layout.h"
+#include "ui/views/layout/grid_layout.h"
+
+namespace payments {
+
+std::unique_ptr<views::View> CreatePaymentView(
+    const base::string16& title, views::View* content_view) {
+  std::unique_ptr<views::View> view = base::MakeUnique<views::View>();
+  view->set_background(views::Background::CreateSolidBackground(SK_ColorWHITE));
+
+  // Paint the sheets to layers, otherwise the MD buttons (which do paint to a
+  // layer) won't do proper clipping.
+  view->SetPaintToLayer(true);
+
+  views::GridLayout* layout = new views::GridLayout(view.get());
+  view->SetLayoutManager(layout);
+  views::ColumnSet* columns = layout->AddColumnSet(0);
+  columns->AddColumn(views::GridLayout::FILL, views::GridLayout::CENTER,
+                     1, views::GridLayout::USE_PREF, 0, 0);
+
+  layout->StartRow(0, 0);
+  layout->AddView(new views::Label(title));
+
+  layout->StartRow(0, 0);
+  layout->AddView(content_view);
+
+  return view;
+}
+
+}  // namespace payments