Don't fall back to default incognito colors and tints when using a

chrome/browser/themes/theme_service.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/themes/theme_service.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 480 matching lines @@
           SK_ColorWHITE, GetColor(kLabelBackground, incognito));
     case ThemeProperties::COLOR_SUPERVISED_USER_LABEL_BACKGROUND:
       return color_utils::BlendTowardOppositeLuma(
           GetColor(ThemeProperties::COLOR_FRAME, incognito), 0x80);
     case ThemeProperties::COLOR_SUPERVISED_USER_LABEL_BORDER:
       return color_utils::AlphaBlend(GetColor(kLabelBackground, incognito),
                                      SK_ColorBLACK, 230);
 #endif
   }
 
-  return ThemeProperties::GetDefaultColor(id, incognito);
+  // Always fall back to the non-incognito color when there's a custom theme
+  // because the default (classic) incognito color may be dramatically different
+  // (optimized for a light-on-dark color).
+  return ThemeProperties::GetDefaultColor(id, incognito && !theme_supplier_);
 }
 
 color_utils::HSL ThemeService::GetTint(int id, bool incognito) const {
   DCHECK(CalledOnValidThread());
 
   color_utils::HSL hsl;
   if (theme_supplier_ && theme_supplier_->GetTint(id, &hsl))
     return hsl;
 
-  return ThemeProperties::GetDefaultTint(id, incognito);
+  // Always fall back to the non-incognito tint when there's a custom theme.
+  // See comment in GetDefaultColor().
+  return ThemeProperties::GetDefaultTint(id, incognito && !theme_supplier_);
 }
 
 void ThemeService::ClearAllThemeData() {
   if (!ready_)
     return;
 
   SwapThemeSupplier(nullptr);
 
   // Clear our image cache.
   FreePlatformCaches();
@@ skipping 332 matching lines @@
 
 #if defined(ENABLE_SUPERVISED_USERS)
 bool ThemeService::IsSupervisedUser() const {
   return profile_->IsSupervised();
 }
 
 void ThemeService::SetSupervisedUserTheme() {
   SetCustomDefaultTheme(new SupervisedUserTheme);
 }
 #endif