[Web Payments] Implement the CVC Unmask dialog.

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

 // Copyright 2017 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_sheet_controller.h"
 
 #include "chrome/browser/ui/views/payments/payment_request_dialog_view.h"
 #include "chrome/browser/ui/views/payments/payment_request_dialog_view_ids.h"
 #include "chrome/browser/ui/views/payments/payment_request_views_util.h"
 #include "components/payments/content/payment_request.h"
@@ skipping 87 matching lines @@
   layout->StartRow(0, 0);
   // |header_view| will be deleted when |view| is.
   layout->AddView(
       CreateSheetHeaderView(ShouldShowHeaderBackArrow(), GetSheetTitle(), this)
           .release());
 
   layout->StartRow(1, 0);
   // |content_view| will go into a views::ScrollView so it needs to be sized now
   // otherwise it'll be sized to the ScrollView's viewport height, preventing
   // the scroll bar from ever being shown.
-  content_view_->SizeToPreferredSize();
+  views::View* pane = new views::View;
+  views::GridLayout* pane_layout = new views::GridLayout(pane);
+  views::ColumnSet* pane_columns = pane_layout->AddColumnSet(0);
+  pane_columns->AddColumn(views::GridLayout::Alignment::FILL,
+                          views::GridLayout::Alignment::LEADING, 0,
+                          views::GridLayout::SizeType::FIXED, 450, 450);
+  pane->SetLayoutManager(pane_layout);
+  pane_layout->StartRow(0, 0);
+  pane_layout->AddView(content_view_);
+  pane->SizeToPreferredSize();
 
   std::unique_ptr<views::ScrollView> scroll =
       base::MakeUnique<views::ScrollView>();
   scroll->EnableViewPortLayer();
   scroll->set_hide_horizontal_scrollbar(true);
-  scroll->SetContents(content_view_);
+  scroll->SetContents(pane);
   layout->AddView(scroll.release());
 
   layout->StartRow(0, 0);
   layout->AddView(CreateFooterView().release());
 
   return view;
 }
 
 std::unique_ptr<views::View> PaymentRequestSheetController::CreateFooterView() {
   std::unique_ptr<views::View> container = base::MakeUnique<views::View>();
@@ skipping 38 matching lines @@
   button->set_tag(static_cast<int>(PaymentRequestCommonTags::CLOSE_BUTTON_TAG));
   button->set_id(static_cast<int>(DialogViewID::CANCEL_BUTTON));
   trailing_buttons_container->AddChildView(button);
 
   layout->AddView(trailing_buttons_container.release());
 
   return container;
 }
 
 }  // namespace payments