Update CrOS logout button for MD.

ui/views/controls/button/md_text_button.cc

 // Copyright 2015 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/md_text_button.h"
 
 #include "base/i18n/case_conversion.h"
 #include "ui/base/material_design/material_design_controller.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/color_utils.h"
@@ skipping 118 matching lines @@
   paint.setColor(SkColorSetA(view->GetNativeTheme()->GetSystemColor(
                                  ui::NativeTheme::kColorId_CallToActionColor),
                              alpha));
   paint.setStyle(SkPaint::kStroke_Style);
   paint.setStrokeWidth(thickness);
   gfx::RectF rect(view->GetLocalBounds());
   rect.Inset(gfx::InsetsF(thickness / 2.f));
   canvas->DrawRoundRect(rect, kFocusBorderCornerRadius, paint);
 }
 
+void MdTextButton::AdjustFontSize(int size_delta) {
+  SetFontList(GetFontList().DeriveWithSizeDelta(size_delta));
+  UpdatePaddingForFont();
+}
+
 void MdTextButton::SetCallToAction(bool cta) {
   if (is_cta_ == cta)
     return;
 
   is_cta_ = cta;
   focus_ring_->set_thickness(cta ? kFocusBorderThicknessCta
                                  : kFocusBorderThickness);
   UpdateColors();
 }
 
@@ skipping 65 matching lines @@
     : LabelButton(listener, base::string16()),
       focus_ring_(new internal::MdFocusRing()),
       is_cta_(false) {
   SetInkDropMode(InkDropMode::ON);
   set_has_ink_drop_action_on_click(true);
   SetHorizontalAlignment(gfx::ALIGN_CENTER);
   SetFocusForPlatform();
   SetMinSize(gfx::Size(kMinWidth, 0));
   SetFocusPainter(nullptr);
   label()->SetAutoColorReadabilityEnabled(false);
-  SetFontList(GetMdFontList());
-
   AddChildView(focus_ring_);
   focus_ring_->SetVisible(false);
   set_request_focus_on_press(false);
+  SetFontList(GetMdFontList());

[sky, 2016/07/27 19:57:07]

As anyone can call SetFontList, shouldn't you make it so that when the font
changes you automatically update padding?

[Evan Stade, 2016/07/27 20:09:47]

are you suggesting making SetFontList virtual? I'm kinda hoping no one will want
to (or be allowed to) use that function on MdTextButtons although there's
nothing enforcing that today. If we make the API more restrictive, like
AdjustFontSize(), it encourages people to do the right thing. Here's an example
of existing usage that I think should be discouraged:

just_once_button_->SetFontList(gfx::FontList("Roboto-medium, 13px"));

When just_once_button_ is an MdTextButton this should instead be
just_once_button_->AdjustFontSize(1);

Most usages of SetFontList appear to use FontStyle, e.g.

  no_show_checkbox_->SetFontList(
      ui::ResourceBundle::GetSharedInstance().GetFontList(
      ui::ResourceBundle::MediumFont));

and I agree with Trent's comment here[1] that it should be phased out.

[1]
https://cs.chromium.org/chromium/src/ui/base/resource/resource_bundle.h?rcl=1...

+  UpdatePaddingForFont();
+}
 
+MdTextButton::~MdTextButton() {}
+
+void MdTextButton::UpdatePaddingForFont() {
   // Top and bottom padding depend on the font. Example: if font cap height is
   // 9dp, use 8dp bottom padding and 7dp top padding to total 24dp.
   const gfx::FontList& font = label()->font_list();
   int text_height = font.GetCapHeight();
   int even_text_height = text_height - (text_height % 2);
   const int top_padding = even_text_height - (text_height - even_text_height);
   const int bottom_padding = even_text_height;
   DCHECK_EQ(3 * even_text_height, top_padding + text_height + bottom_padding);
 
   const int inbuilt_top_padding = font.GetBaseline() - font.GetCapHeight();
   const int inbuilt_bottom_padding =
       font.GetHeight() - label()->font_list().GetBaseline();
 
   // TODO(estade): can we get rid of the platform style border hoopla if
   // we apply the MD treatment to all buttons, even GTK buttons?
   SetBorder(Border::CreateEmptyBorder(
       top_padding - inbuilt_top_padding, kHorizontalPadding,
       bottom_padding - inbuilt_bottom_padding, kHorizontalPadding));
 }
 
-MdTextButton::~MdTextButton() {}
-
 void MdTextButton::UpdateColors() {
   ui::NativeTheme::ColorId fg_color_id =
       is_cta_ ? ui::NativeTheme::kColorId_TextOnCallToActionColor
               : ui::NativeTheme::kColorId_ButtonEnabledColor;
 
   ui::NativeTheme* theme = GetNativeTheme();
   if (!explicitly_set_normal_color())
     LabelButton::SetEnabledTextColors(theme->GetSystemColor(fg_color_id));
 
   SkColor text_color = label()->enabled_color();
@@ skipping 11 matching lines @@
   SkColor stroke_color = (is_cta_ || color_utils::IsDark(text_color))
                              ? SkColorSetA(SK_ColorBLACK, kStrokeOpacity)
                              : SkColorSetA(SK_ColorWHITE, 2 * kStrokeOpacity);
 
   set_background(Background::CreateBackgroundPainter(
       true, Painter::CreateRoundRectWith1PxBorderPainter(
                 bg_color, stroke_color, kInkDropSmallCornerRadius)));
 }
 
 }  // namespace views