Material Design: Fix MdLabelButton not updating text colors on theme changes

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 359 matching lines @@
       style_));
   return border;
 }
 
 void LabelButton::SetBorder(std::unique_ptr<Border> border) {
   border_is_themed_border_ = false;
   View::SetBorder(std::move(border));
   ResetCachedPreferredSize();
 }
 
+void LabelButton::ResetExplicitnessOfEnabledTextColors() {
+  for (ButtonState state : {STATE_NORMAL, STATE_HOVERED, STATE_PRESSED})

[Evan Stade, 2017/01/07 01:31:40]

hmm, this is not quite as I imagined, because STATE_DISABLED is missing. that is
what you want that for the MdTextButton case but perhaps not for the general
case. It would be nice to reuse this at least in two places (MdTextButton and
below in ResetColorsFromNativeTheme).

Options that come to mind:
a) create a SetTextColorInternal that does everything except flip the explicit
bit, or
b) create a |setting_text_colors_from_theme_| boolean which, when true, disables
flipping the explicit bit
c) expose explicitly_set_colors() and set_explicitly_set_colors(), then do:

auto old_explicitly_set_colors = explicitly_set_colors();
SetEnabledTextColors(...);
set_explicitly_set_colors(old_explicitly_set_colors);

[Tom (Use chromium acct), 2017/01/07 02:35:11]

Done.  I liked (c) the most so I went with that

+    explicitly_set_colors_[state] = false;
+}
+
 gfx::Rect LabelButton::GetChildAreaBounds() {
   return GetLocalBounds();
 }
 
 void LabelButton::SetFontList(const gfx::FontList& font_list) {
   cached_normal_font_list_ = font_list;
   if (PlatformStyle::kDefaultLabelButtonHasBoldFont) {
     cached_bold_font_list_ = font_list.DeriveWithWeight(
         GetValueBolderThan(font_list.GetFontWeight()));
     if (is_default_) {
@@ skipping 214 matching lines @@
           : PlatformStyle::TextColorForButton(button_state_colors_, *this);
   if (state() != STATE_DISABLED && label_->enabled_color() != color)
     label_->SetEnabledColor(color);
 }
 
 bool LabelButton::UseFloodFillInkDrop() const {
   return !GetText().empty();
 }
 
 }  // namespace views