Monitor the system native frame color on Win 10.

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 "grit/theme_resources.h"
+#include "skia/ext/skia_utils_win.h"
+#include "ui/base/win/shell.h"
+
+ThemeServiceWin::ThemeServiceWin() {
+  // This just checks for Windows 10 instead of calling ShouldUseDwmFrameColor()
+  // because we want to monitor the frame color even when a custom frame is in
+  // use, so that it will be correct if at any time the user switches to the
+  // native frame.
+  if (base::win::GetVersion() >= base::win::VERSION_WIN10) {
+    dwm_key_.reset(new base::win::RegKey(
+        HKEY_CURRENT_USER, L"SOFTWARE\\Microsoft\\Windows\\DWM", KEY_READ));
+    OnDwmKeyUpdated();
+  }
+}
+
+ThemeServiceWin::~ThemeServiceWin() {
+}
+
+bool ThemeServiceWin::ShouldUseNativeFrame() const {
+  return !HasCustomImage(IDR_THEME_FRAME) && ui::win::IsAeroGlassEnabled();
+}
+
+SkColor ThemeServiceWin::GetDefaultColor(int id, bool incognito) const {
+  if (ShouldUseDwmFrameColor()) {
+    // Active native windows on Windows 10 may have a custom frame color.
+    if (id == ThemeProperties::COLOR_FRAME)
+      return dwm_frame_color_;
+
+    // Inactive native windows on Windows 10 always have a white frame.
+    if (id == ThemeProperties::COLOR_FRAME_INACTIVE)
+        return SK_ColorWHITE;
+  }
+
+  return ThemeService::GetDefaultColor(id, incognito);
+}
+
+bool ThemeServiceWin::ShouldUseDwmFrameColor() const {
+  return ShouldUseNativeFrame() &&
+         (base::win::GetVersion() >= base::win::VERSION_WIN10);
+}
+
+void ThemeServiceWin::OnDwmKeyUpdated() {
+  // Attempt to read the accent color.
+  DWORD accent_color, color_prevalence;
+  dwm_frame_color_ =
+      ((dwm_key_->ReadValueDW(L"ColorPrevalence", &color_prevalence) ==
+        ERROR_SUCCESS) &&
+       (color_prevalence == 1) &&
+       (dwm_key_->ReadValueDW(L"AccentColor", &accent_color) == ERROR_SUCCESS))
+          ? skia::COLORREFToSkColor(accent_color)
+          : SK_ColorWHITE;
+
+  // Watch for future changes.
+  if (!dwm_key_->StartWatching(base::Bind(
+          &ThemeServiceWin::OnDwmKeyUpdated, base::Unretained(this))))
+    dwm_key_.reset();
+}