Update some secondary UI buttons to MD style.

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/color_utils.h"
 #include "ui/native_theme/native_theme.h"
@@ skipping 95 matching lines @@
   UseMdFocusRing();
   label()->SetAutoColorReadabilityEnabled(false);
 }
 
 MdTextButton::~MdTextButton() {}
 
 void MdTextButton::UpdateColorsFromNativeTheme() {
   ui::NativeTheme::ColorId fg_color_id = ui::NativeTheme::kColorId_NumColors;
   switch (cta_) {
     case NO_CALL_TO_ACTION:
-      fg_color_id = ui::NativeTheme::kColorId_ButtonEnabledColor;
+      // When there's no call to action, respect a color override if one has
+      // been set. For other call to action states, don't let individual buttons
+      // specify a color.
+      if (!explicitly_set_normal_color())
+        fg_color_id = ui::NativeTheme::kColorId_ButtonEnabledColor;
       break;
     case WEAK_CALL_TO_ACTION:
       fg_color_id = ui::NativeTheme::kColorId_CallToActionColor;
       break;
     case STRONG_CALL_TO_ACTION:
       fg_color_id = ui::NativeTheme::kColorId_TextOnCallToActionColor;
       break;
   }
   ui::NativeTheme* theme = GetNativeTheme();
-  SetEnabledTextColors(theme->GetSystemColor(fg_color_id));
+  if (fg_color_id != ui::NativeTheme::kColorId_NumColors)
+    SetEnabledTextColors(theme->GetSystemColor(fg_color_id));
 
   set_background(
       cta_ == STRONG_CALL_TO_ACTION
           ? Background::CreateBackgroundPainter(
                 true, Painter::CreateSolidRoundRectPainter(
                           theme->GetSystemColor(
                               ui::NativeTheme::kColorId_CallToActionColor),
                           kInkDropSmallCornerRadius))
           : nullptr);
 }
 
 }  // namespace views