Some more fixes to cros system tray icons (esp. screen tray items)

ash/common/system/tray/tray_item_view.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_item_view.h"
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/shelf/wm_shelf_util.h"
 #include "ash/common/system/tray/system_tray.h"
 #include "ash/common/system/tray/system_tray_item.h"
@@ skipping 65 matching lines @@
     views::View::SetVisible(true);
   }
 }
 
 int TrayItemView::GetAnimationDurationMS() {
   return kTrayItemAnimationDurationMS;
 }
 
 gfx::Size TrayItemView::GetPreferredSize() const {
   gfx::Size size;
+  DCHECK_EQ(1, child_count());

[tdanderson, 2016/11/01 20:25:08]

Can you please add documentation somewhere in tray_item_view.h clarifying that
exactly one of |label_| and |image_view_| is non-null?

[Evan Stade, 2016/11/01 23:45:17]

Done.

   if (MaterialDesignController::UseMaterialDesignSystemIcons()) {
     gfx::Size inner_size = views::View::GetPreferredSize();
-    if (image_view_ && child_count() == 1)
+    if (image_view_)
       inner_size = gfx::Size(kTrayIconSize, kTrayIconSize);
     gfx::Rect rect(inner_size);
     rect.Inset(gfx::Insets(-GetTrayConstant(TRAY_IMAGE_ITEM_PADDING)));
     size = rect.size();
   } else {
     size = views::View::GetPreferredSize();
     if (IsHorizontalAlignment(owner()->system_tray()->shelf_alignment()))
       size.set_height(kTrayIconHeight);
     else
       size.set_width(kTrayIconWidth);
@@ skipping 36 matching lines @@
 void TrayItemView::AnimationEnded(const gfx::Animation* animation) {
   if (animation->GetCurrentValue() < 0.1)
     views::View::SetVisible(false);
 }
 
 void TrayItemView::AnimationCanceled(const gfx::Animation* animation) {
   AnimationEnded(animation);
 }
 
 }  // namespace ash