App list: The line under folder headings has a fixed margin.

ui/app_list/views/folder_header_view.cc

 // Copyright (c) 2013 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 "ui/app_list/views/folder_header_view.h"
 
 #include <algorithm>
 
 #include "base/strings/utf_string_conversions.h"
 #include "ui/app_list/app_list_constants.h"
 #include "ui/app_list/app_list_folder_item.h"
 #include "ui/app_list/views/app_list_folder_view.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/canvas.h"
 #include "ui/resources/grit/ui_resources.h"
 #include "ui/strings/grit/ui_strings.h"
 #include "ui/views/border.h"
 #include "ui/views/controls/button/image_button.h"
 #include "ui/views/controls/textfield/textfield.h"
 #include "ui/views/painter.h"
 
 namespace app_list {
 
 namespace {
 
 const int kPreferredWidth = 360;
 const int kPreferredHeight = 48;
 const int kIconDimension = 24;
 const int kPadding = 14;
-const int kBottomSeparatorWidth = 380;
+const int kBottomSeparatorPadding = 9;
 const int kBottomSeparatorHeight = 1;
 const int kMaxFolderNameWidth = 300;
 
 const SkColor kHintTextColor = SkColorSetRGB(0xA0, 0xA0, 0xA0);
 
 }  // namespace
 
 class FolderHeaderView::FolderNameView : public views::Textfield {
  public:
   FolderNameView() {
@@ skipping 144 matching lines @@
 }
 
 void FolderHeaderView::OnPaint(gfx::Canvas* canvas) {
   views::View::OnPaint(canvas);
 
   gfx::Rect rect(GetContentsBounds());
   if (rect.IsEmpty() || !folder_name_visible_)
     return;
 
   // Draw bottom separator line.
-  rect.set_x((rect.width() - kBottomSeparatorWidth) / 2 + rect.x());
-  rect.set_y(rect.y() + rect.height() - kBottomSeparatorHeight);
-  rect.set_width(kBottomSeparatorWidth);
+  rect.Inset(kBottomSeparatorPadding, 0);
+  rect.set_y(rect.bottom() - kBottomSeparatorHeight);
   rect.set_height(kBottomSeparatorHeight);
   canvas->FillRect(rect, kTopSeparatorColor);
 }
 
 void FolderHeaderView::ContentsChanged(views::Textfield* sender,
                                        const base::string16& new_contents) {
   // Temporarily remove from observer to ignore data change caused by us.
   if (!folder_item_)
     return;
 
@@ skipping 13 matching lines @@
 void FolderHeaderView::ButtonPressed(views::Button* sender,
                                      const ui::Event& event) {
   delegate_->NavigateBack(folder_item_, event);
 }
 
 void FolderHeaderView::ItemNameChanged() {
   Update();
 }
 
 }  // namespace app_list