Ensure UI elements contrast with the right frame color.

chrome/browser/themes/theme_service_win.cc

 // Copyright 2016 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_win.h"
 
 #include "base/bind.h"
 #include "base/win/windows_version.h"
 #include "chrome/browser/themes/theme_properties.h"
 #include "chrome/browser/win/titlebar_config.h"
@@ skipping 25 matching lines @@
   const bool use_native_frame_if_enabled =
       ShouldCustomDrawSystemTitlebar() || !HasCustomImage(IDR_THEME_FRAME);
   return use_native_frame_if_enabled && ui::win::IsAeroGlassEnabled();
 }
 
 SkColor ThemeServiceWin::GetDefaultColor(int id, bool incognito) const {
   if (DwmColorsAllowed()) {
     if (id == ThemeProperties::COLOR_ACCENT_BORDER)
       return dwm_accent_border_color_;
 
-    if (use_dwm_frame_color_) {
-      // Incognito frame is the same as normal when we're using DWM colors.
-      if (id == ThemeProperties::COLOR_FRAME)
+    // When we're custom-drawing the titlebar we want to use either the colors
+    // we calculated in OnDwmKeyUpdated() or the default colors. When we're not
+    // custom-drawing the titlebar we want to match the color Windows actually
+    // uses because some things (like the incognito icon) use this color to
+    // decide whether they should draw in light or dark mode. Incognito colors
+    // should be the same as non-incognito in all cases here.
+    if (id == ThemeProperties::COLOR_FRAME) {
+      if (use_dwm_frame_color_)
         return dwm_frame_color_;
-      if (id == ThemeProperties::COLOR_FRAME_INACTIVE)
+      if (!ShouldCustomDrawSystemTitlebar())
+        return SK_ColorWHITE;
+      // Fallthrough and use default.

[Evan Stade, 2016/12/29 16:34:07]

nit: "Fall through"

[Bret, 2017/01/03 22:49:53]

Done.

+    }
+    if (id == ThemeProperties::COLOR_FRAME_INACTIVE) {
+      if (!ShouldCustomDrawSystemTitlebar()) {
+        if (inactive_frame_color_from_registry_)

[Evan Stade, 2016/12/29 16:34:07]

nit: ternary?

[Bret, 2017/01/03 22:49:53]

Done.

+          return dwm_inactive_frame_color_;
+        return SK_ColorWHITE;
+      }
+      if (use_dwm_frame_color_)
         return dwm_inactive_frame_color_;
+      // Fallthrough and use default.
     }
   }
 
   return ThemeService::GetDefaultColor(id, incognito);
 }
 
 bool ThemeServiceWin::DwmColorsAllowed() const {
   return ShouldUseNativeFrame() &&
          (base::win::GetVersion() >= base::win::VERSION_WIN10);
 }
 
 void ThemeServiceWin::OnDwmKeyUpdated() {
   DWORD accent_color, color_prevalence;
   use_dwm_frame_color_ =

[Evan Stade, 2016/12/29 16:34:07]

can we use base::Optional for dwm_frame_color_ (and perhaps in more places) to
cut down on the number of variables? might make things easier to understand in
GetDefaultColor, which is becoming fairly byzantine.

[Bret, 2017/01/03 22:49:52]

I made this change and it helps a little bit. But the logic itself is kind of
byzantine unfortunately.

       dwm_key_->ReadValueDW(L"AccentColor", &accent_color) == ERROR_SUCCESS &&
       dwm_key_->ReadValueDW(L"ColorPrevalence", &color_prevalence) ==
           ERROR_SUCCESS &&
       color_prevalence == 1;
+  inactive_frame_color_from_registry_ = false;
   if (use_dwm_frame_color_) {
     dwm_frame_color_ = skia::COLORREFToSkColor(accent_color);
     DWORD accent_color_inactive;
     if (dwm_key_->ReadValueDW(L"AccentColorInactive", &accent_color_inactive) ==
         ERROR_SUCCESS) {
       dwm_inactive_frame_color_ =
           skia::COLORREFToSkColor(accent_color_inactive);
+      inactive_frame_color_from_registry_ = true;
     } else {
       // Tint to create inactive color. Always use the non-incognito version of
       // the tint, since the frame should look the same in both modes.
       dwm_inactive_frame_color_ = color_utils::HSLShift(
           dwm_frame_color_,
           GetTint(ThemeProperties::TINT_FRAME_INACTIVE, false));
     }
   }
 
   dwm_accent_border_color_ = SK_ColorWHITE;
@@ skipping 21 matching lines @@
     dwm_accent_border_color_ = color_utils::AlphaBlend(
         input_color, SkColorSetRGB(0xd9, 0xd9, 0xd9),
         gfx::ToRoundedInt(255 * colorization_color_balance / 100.f));
   }
 
   // Watch for future changes.
   if (!dwm_key_->StartWatching(base::Bind(
           &ThemeServiceWin::OnDwmKeyUpdated, base::Unretained(this))))
     dwm_key_.reset();
 }