Update CrOS logout button for MD.

ui/views/controls/button/label_button.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 "ui/views/controls/button/label_button.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 174 matching lines @@
     cached_bold_font_list_ = font_list.DeriveWithWeight(
         GetValueBolderThan(font_list.GetFontWeight()));
     if (is_default_) {
       label_->SetFontList(cached_bold_font_list_);
       return;
     }
   }
   label_->SetFontList(cached_normal_font_list_);
 }
 
+void LabelButton::AdjustFontSize(int font_size_delta) {
+  LabelButton::SetFontList(GetFontList().DeriveWithSizeDelta(font_size_delta));
+}
+
 void LabelButton::SetElideBehavior(gfx::ElideBehavior elide_behavior) {
   label_->SetElideBehavior(elide_behavior);
 }
 
 void LabelButton::SetHorizontalAlignment(gfx::HorizontalAlignment alignment) {
   DCHECK_NE(gfx::ALIGN_TO_HEAD, alignment);
   horizontal_alignment_ = alignment;
   InvalidateLayout();
 }
 
@@ skipping 384 matching lines @@
 void LabelButton::ResetLabelEnabledColor() {
   const SkColor color =
       explicitly_set_colors_[state()]
           ? button_state_colors_[state()]
           : PlatformStyle::TextColorForButton(button_state_colors_, *this);
   if (state() != STATE_DISABLED && label_->enabled_color() != color)
     label_->SetEnabledColor(color);
 }
 
 }  // namespace views