First stab at MD text buttons

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/gfx/render_text.h"
+#include "ui/native_theme/native_theme.h"
+
+namespace views {
+
+namespace {
+
+// Inset between clickable region border and button contents (text).
+const int kHorizontalPadding = 12;
+const int kVerticalPadding = 6;
+
+// Minimum size to reserve for the button contents.
+const int kMinWidth = 48;
+
+const gfx::FontList& GetFontList() {
+  static base::LazyInstance<gfx::FontList>::Leaky font_list =
+      LAZY_INSTANCE_INITIALIZER;
+  return font_list.Get();
+}
+
+}  // namespace
+
+MdTextButton::MdTextButton(ButtonListener* listener, const base::string16& text)
+    : CustomButton(listener),
+      render_text_(gfx::RenderText::CreateInstance()) {
+  render_text_->SetFontList(GetFontList());
+  render_text_->SetCursorEnabled(false);
+  render_text_->SetText(base::i18n::ToUpper(text));
+
+  SetFocusable(true);
+}
+
+MdTextButton::~MdTextButton() {}
+
+void MdTextButton::OnPaint(gfx::Canvas* canvas) {
+  UpdateColor();
+  gfx::Rect rect = GetLocalBounds();
+  rect.Inset(kHorizontalPadding, kVerticalPadding);
+  render_text_->SetDisplayRect(rect);
+  render_text_->Draw(canvas);
+}
+
+gfx::Size MdTextButton::GetPreferredSize() const {
+  gfx::Size size = render_text_->GetStringSize();
+  size.SetToMax(gfx::Size(kMinWidth, 0));
+  size.Enlarge(kHorizontalPadding * 2, kVerticalPadding * 2);
+  return size;
+}
+
+void MdTextButton::UpdateColor() {
+  // TODO(estade): handle call to action theming and other things that can
+  // affect the text color.
+  render_text_->SetColor(GetNativeTheme()->GetSystemColor(
+      enabled() ? ui::NativeTheme::kColorId_MdTextButtonEnabledColor
+                : ui::NativeTheme::kColorId_MdTextButtonDisabledColor));
+}
+
+}  // namespace views