Monitor the system native frame color on Win 10.

chrome/browser/themes/theme_service.h

Index: chrome/browser/themes/theme_service.h
diff --git a/chrome/browser/themes/theme_service.h b/chrome/browser/themes/theme_service.h
index cabfefe2954c635e862f81c3021ee44ca51c20e8..7f2aae589f708324e1efcabd087a072dd21dd5a4 100644
--- a/chrome/browser/themes/theme_service.h
+++ b/chrome/browser/themes/theme_service.h
@@ -22,6 +22,10 @@
 #include "content/public/browser/notification_registrar.h"
 #include "ui/base/theme_provider.h"
 
+#if defined(OS_WIN)
+#include "base/win/registry.h"
+#endif
+
 class CustomThemeSupplier;
 class BrowserThemePack;
 class ThemeSyncableService;
@@ -259,6 +263,16 @@ class ThemeService : public base::NonThreadSafe,
   void SetSupervisedUserTheme();
 #endif
 
+#if defined(OS_WIN)
+  // Returns true if the window frame color is determined by the DWM, i.e. this
+  // is a native frame on Win 10+.
+  bool ShouldUseDwmFrameColor() const;
+
+  // Callback executed when |dwm_key_| is updated.  This re-reads the active
+  // frame color and updates |dwm_frame_color_|.
+  void OnDwmKeyUpdated();
+#endif
+
 #if defined(OS_MACOSX)
   // |nsimage_cache_| retains the images it has cached.
   typedef std::map<int, NSImage*> NSImageMap;
@@ -287,6 +301,15 @@ class ThemeService : public base::NonThreadSafe,
   // The number of infobars currently displayed.
   int number_of_infobars_;
 
+#if defined(OS_WIN)
+  // Registry key containing the params that determine the DWM frame color.
+  // This is only initialized on Windows 10.
+  scoped_ptr<base::win::RegKey> dwm_key_;
+
+  // The DWM frame color, if available; white otherwise.
+  SkColor dwm_frame_color_;
+#endif
+
   content::NotificationRegistrar registrar_;
 
   scoped_ptr<ThemeSyncableService> theme_syncable_service_;