[top-chrome-md] Allows UpdateMaterialDesignColors to be called before MDC::Initialize()

chrome/browser/ui/libgtk2ui/gtk2_ui.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 "chrome/browser/ui/libgtk2ui/gtk2_ui.h"
 
 #include <math.h>
 #include <pango/pango.h>
 #include <set>
 #include <utility>
@@ skipping 978 matching lines @@
 
   colors_[ThemeProperties::COLOR_TAB_THROBBER_SPINNING] =
       theme->GetSystemColor(ui::NativeTheme::kColorId_ThrobberSpinningColor);
   colors_[ThemeProperties::COLOR_TAB_THROBBER_WAITING] =
       theme->GetSystemColor(ui::NativeTheme::kColorId_ThrobberWaitingColor);
 }
 
 void Gtk2UI::UpdateMaterialDesignColors() {
   // TODO(varkha): This should be merged back into LoadGtkValues() once Material
   // Design is on unconditionally.
-  if (ui::MaterialDesignController::IsModeMaterial()) {
-    NativeThemeGtk2* theme = NativeThemeGtk2::instance();
-    SkColor label_color =
-        theme->GetSystemColor(ui::NativeTheme::kColorId_LabelEnabledColor);
-    colors_[ThemeProperties::COLOR_BACKGROUND_TAB_TEXT] =
-        color_utils::BlendTowardOppositeLuma(label_color, 50);
+  // Early return when Material Design Controller is not initialized yet. This
+  // is harmless and the colors will get updated when this method is called
+  // again after the initialization. See http://crbug.com/622234.
+  if (!ui::MaterialDesignController::is_mode_initialized() ||
+      !ui::MaterialDesignController::IsModeMaterial()) {
+    return;
   }
+  NativeThemeGtk2* theme = NativeThemeGtk2::instance();
+  SkColor label_color =
+      theme->GetSystemColor(ui::NativeTheme::kColorId_LabelEnabledColor);
+  colors_[ThemeProperties::COLOR_BACKGROUND_TAB_TEXT] =
+      color_utils::BlendTowardOppositeLuma(label_color, 50);
 }
 
 SkColor Gtk2UI::BuildFrameColors() {
   NativeThemeGtk2* theme = NativeThemeGtk2::instance();
   SkColor frame_color =
       theme->GetSystemColor(ui::NativeTheme::kColorId_WindowBackground);
   SkColor temp_color;
 
 #if GTK_MAJOR_VERSION == 2
   color_utils::HSL kDefaultFrameShift = { -1, -1, 0.4 };
@@ skipping 387 matching lines @@
   // Blacklist scaling factors <130% (crbug.com/484400) and round
   // to 1 decimal to prevent rendering problems (crbug.com/485183).
   return scale < 1.3f ? 1.0f : roundf(scale * 10) / 10;
 }
 
 }  // namespace libgtk2ui
 
 views::LinuxUI* BuildGtk2UI() {
   return new libgtk2ui::Gtk2UI;
 }