More closely align palette to spec.

ash/common/system/tray/tray_popup_header_button.cc

Index: ash/common/system/tray/tray_popup_header_button.cc
diff --git a/ash/common/system/tray/tray_popup_header_button.cc b/ash/common/system/tray/tray_popup_header_button.cc
index bb15d503600002a69ca0f4375af118ccb5f9873b..2dfde7d041f34518feb5c79f45b6ef2bc621b662 100644
--- a/ash/common/system/tray/tray_popup_header_button.cc
+++ b/ash/common/system/tray/tray_popup_header_button.cc
@@ -12,17 +12,25 @@
 
 namespace ash {
 
+namespace {
+
+const gfx::ImageSkia* GetImageForResourceId(int resource_id) {
+  ui::ResourceBundle& bundle = ui::ResourceBundle::GetSharedInstance();
+  return bundle.GetImageNamed(resource_id).ToImageSkia();
+}
+
+}  // namespace
+
 // static
 const char TrayPopupHeaderButton::kViewClassName[] =
     "tray/TrayPopupHeaderButton";
 
 TrayPopupHeaderButton::TrayPopupHeaderButton(views::ButtonListener* listener,
-                                             int icon_resource_id,
+                                             const gfx::ImageSkia& icon,
                                              int accessible_name_id)
     : views::ToggleImageButton(listener) {
   ui::ResourceBundle& bundle = ui::ResourceBundle::GetSharedInstance();
-  SetImage(views::Button::STATE_NORMAL,
-           bundle.GetImageNamed(icon_resource_id).ToImageSkia());
+  SetImage(views::Button::STATE_NORMAL, &icon);
   SetImageAlignment(views::ImageButton::ALIGN_CENTER,
                     views::ImageButton::ALIGN_MIDDLE);
   SetAccessibleName(bundle.GetLocalizedString(accessible_name_id));
@@ -38,7 +46,9 @@ TrayPopupHeaderButton::TrayPopupHeaderButton(views::ButtonListener* listener,
                                              int enabled_resource_id_hover,
                                              int disabled_resource_id_hover,
                                              int accessible_name_id)
-    : TrayPopupHeaderButton(listener, enabled_resource_id, accessible_name_id) {
+    : TrayPopupHeaderButton(listener,
+                            *GetImageForResourceId(enabled_resource_id),
+                            accessible_name_id) {

[stevenjb, 2016/08/24 15:58:57]

This is awkward and may be tricky to debug if GetImageForResourceId were to
return null. Instead, can we move the code in the constructor above into a
private method and call that from each constructor instead?

[jdufault, 2016/08/24 18:48:06]

Done.

   ui::ResourceBundle& bundle = ui::ResourceBundle::GetSharedInstance();
   SetToggledImage(views::Button::STATE_NORMAL,
                   bundle.GetImageNamed(disabled_resource_id).ToImageSkia());