Try to improve toolbar separator coloration for themed browser windows.

chrome/browser/themes/theme_properties.cc

 // Copyright (c) 2013 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_properties.h"
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/strings/string_split.h"
@@ skipping 66 matching lines @@
 constexpr color_utils::HSL kDefaultTintFrame = {-1, -1, -1};
 constexpr color_utils::HSL kDefaultTintFrameInactive = {-1, -1, 0.9};
 constexpr color_utils::HSL kDefaultTintFrameIncognito = {-1, 0.2, 0.35};
 constexpr color_utils::HSL kDefaultTintFrameIncognitoInactive = {-1, 0.2, 0.87};
 constexpr color_utils::HSL kDefaultTintBackgroundTab = {-1, -1, 0.75};
 
 // ----------------------------------------------------------------------------
 // Defaults for properties which are not stored in the browser theme pack.
 
 constexpr SkColor kDefaultColorControlBackground = SK_ColorWHITE;
-const SkColor kDefaultDetachedBookmarkBarSeparator =
+const SkColor kDefaultToolbarBottomSeparator =
     SkColorSetRGB(0xB6, 0xB4, 0xB6);
-const SkColor kDefaultDetachedBookmarkBarSeparatorIncognito =
+const SkColor kDefaultToolbarBottomSeparatorIncognito =
     SkColorSetRGB(0x28, 0x28, 0x28);
 const SkColor kDefaultToolbarTopSeparator = SkColorSetA(SK_ColorBLACK, 0x40);
 
 #if defined(OS_MACOSX)
 const SkColor kDefaultColorFrameVibrancyOverlay =
     SkColorSetA(SK_ColorBLACK, 0x19);
 const SkColor kDefaultColorFrameVibrancyOverlayIncognito =
     SkColorSetARGB(0xE6, 0x14, 0x16, 0x18);
 const SkColor kDefaultColorToolbarInactive = SkColorSetRGB(0xF6, 0xF6, 0xF6);
 const SkColor kDefaultColorToolbarInactiveIncognito =
@@ skipping 163 matching lines @@
       return TintForUnderline(kDefaultColorNTPSectionLink);
     case COLOR_BUTTON_BACKGROUND:
       return kDefaultColorButtonBackground;
 
     // Properties not stored in theme pack.
     case COLOR_CONTROL_BACKGROUND:
       return kDefaultColorControlBackground;
     case COLOR_BOOKMARK_BAR_INSTRUCTIONS_TEXT:
       return otr ? kDefaultColorBookmarkInstructionsTextIncognito
                  : kDefaultColorBookmarkInstructionsText;
-    case COLOR_TOOLBAR_BOTTOM_SEPARATOR:
     case COLOR_DETACHED_BOOKMARK_BAR_SEPARATOR:
-      return otr ? kDefaultDetachedBookmarkBarSeparatorIncognito
-                 : kDefaultDetachedBookmarkBarSeparator;
+      // We shouldn't reach this case because the color is calculated from
+      // COLOR_TOOLBAR_BOTTOM_SEPARTOR.
+      NOTREACHED();
+      return gfx::kPlaceholderColor;
     case COLOR_DETACHED_BOOKMARK_BAR_BACKGROUND:
       return otr ? kDefaultDetachedBookmarkBarBackgroundIncognito
                  : kDefaultDetachedBookmarkBarBackground;
+    case COLOR_TOOLBAR_BOTTOM_SEPARATOR:
+      return otr ? kDefaultToolbarBottomSeparatorIncognito
+                 : kDefaultToolbarBottomSeparator;
     case COLOR_TOOLBAR_TOP_SEPARATOR:
     case COLOR_TOOLBAR_TOP_SEPARATOR_INACTIVE:
       return kDefaultToolbarTopSeparator;
 #if defined(OS_MACOSX)
     case COLOR_FRAME_VIBRANCY_OVERLAY:
       return otr ? kDefaultColorFrameVibrancyOverlayIncognito
                  : kDefaultColorFrameVibrancyOverlay;
     case COLOR_TOOLBAR_INACTIVE:
       return otr ? kDefaultColorToolbarInactiveIncognito
                  : kDefaultColorToolbarInactive;
@@ skipping 25 matching lines @@
     case COLOR_FRAME_INCOGNITO:
     case COLOR_FRAME_INCOGNITO_INACTIVE:
       NOTREACHED() << "These values should be queried via their respective "
                       "non-incognito equivalents and an appropriate |otr| "
                       "value.";
       return gfx::kPlaceholderColor;
   }
 
   return gfx::kPlaceholderColor;
 }