[ash-md] Makes Wi-Fi header row sticky when network list is scrolled

ash/common/system/tray/tray_constants.cc

 // Copyright (c) 2012 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 "ash/common/system/tray/tray_constants.h"
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "base/logging.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/color_palette.h"
@@ skipping 58 matching lines @@
 const SkColor kHeaderTextColorHover = SkColorSetARGB(0xd3, 0, 0, 0);
 
 const int kTrayPopupMinWidth = 300;
 const int kTrayPopupMaxWidth = 500;
 const int kNotificationIconWidth = 40;
 const int kNotificationButtonWidth = 32;
 const int kTrayNotificationContentsWidth =
     kTrayPopupMinWidth - (kNotificationIconWidth + kNotificationButtonWidth +
                           (kTrayPopupPaddingHorizontal / 2) * 3);
 
+const int kHeaderRowId = -1;
+
 const int kTrayIconSize = 16;
 const SkColor kTrayIconColor = SK_ColorWHITE;
 const int kMenuIconSize = 20;
 const SkColor kMenuIconColor = gfx::kChromeIconGrey;
 const SkColor kMenuIconColorDisabled = SkColorSetA(gfx::kChromeIconGrey, 0x61);
 const int kMenuButtonSize = 48;
 const int kMenuSeparatorVerticalPadding = 4;
 const int kMenuExtraMarginFromLeftEdge = 4;
 
 const int kHitRegionPadding = 4;
@@ skipping 51 matching lines @@
     case TRAY_IME_MENU_ICON:
       return kTrayImeMenuIcon[mode];
     case TRAY_IMAGE_ITEM_PADDING:
       return kTrayImageItemPadding[mode];
   }
   NOTREACHED();
   return 0;
 }
 
 }  // namespace ash