Revert "[Windows] Use dark title bar on dark system theme" (#110890)

dev/integration_tests/flutter_gallery/windows/runner/CMakeLists.txt

@@ -33,7 +33,6 @@ target_compile_definitions(${BINARY_NAME} PRIVATE "NOMINMAX")
 # Add dependency libraries and include directories. Add any application-specific
 # dependencies here.
 target_link_libraries(${BINARY_NAME} PRIVATE flutter flutter_wrapper_app)
-target_link_libraries(${BINARY_NAME} PRIVATE "dwmapi.lib")
 target_include_directories(${BINARY_NAME} PRIVATE "${CMAKE_SOURCE_DIR}")
 
 # Run the Flutter tool portions of the build. This must not be removed.

dev/integration_tests/flutter_gallery/windows/runner/win32_window.cpp

@@ -4,28 +4,14 @@
 
 #include "win32_window.h"
 
-#include <dwmapi.h>
 #include <flutter_windows.h>
 
 #include "resource.h"
 
 namespace {
 
-/// Window attribute that enables dark mode window decorations.
-///
-/// Redefined in case the developer's machine has a Windows SDK older than
-/// version 10.0.22000.0.
-/// See: https://docs.microsoft.com/windows/win32/api/dwmapi/ne-dwmapi-dwmwindowattribute
-#ifndef DWMWA_USE_IMMERSIVE_DARK_MODE
-#define DWMWA_USE_IMMERSIVE_DARK_MODE 20
-#endif
-
 constexpr const wchar_t kWindowClassName[] = L"FLUTTER_RUNNER_WIN32_WINDOW";
 
-constexpr const wchar_t kGetPreferredBrightnessRegKey[] =
-  L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize";
-constexpr const wchar_t kGetPreferredBrightnessRegValue[] = L"AppsUseLightTheme";
-
 // The number of Win32Window objects that currently exist.
 static int g_active_window_count = 0;
 
@@ -144,8 +130,6 @@ bool Win32Window::Create(const std::wstring& title,
     return false;
   }
 
-  UpdateTheme(window);
-
   return OnCreate();
 }
 
@@ -212,10 +196,6 @@ Win32Window::MessageHandler(HWND hwnd,
         SetFocus(child_content_);
       }
       return 0;
-
-    case WM_DWMCOLORIZATIONCOLORCHANGED:
-      UpdateTheme(hwnd);
-      return 0;
   }
 
   return DefWindowProc(window_handle_, message, wparam, lparam);
@@ -271,17 +251,3 @@ bool Win32Window::OnCreate() {
 void Win32Window::OnDestroy() {
   // No-op; provided for subclasses.
 }
-
-void Win32Window::UpdateTheme(HWND const window) {
-  DWORD light_mode;
-  DWORD light_mode_size = sizeof(light_mode);
-  LONG result = RegGetValue(HKEY_CURRENT_USER, kGetPreferredBrightnessRegKey,
-                            kGetPreferredBrightnessRegValue, RRF_RT_REG_DWORD,
-                            nullptr, &light_mode, &light_mode_size);
-
-  if (result == ERROR_SUCCESS) {
-    BOOL enable_dark_mode = light_mode == 0;
-    DwmSetWindowAttribute(window, DWMWA_USE_IMMERSIVE_DARK_MODE,
-                          &enable_dark_mode, sizeof(enable_dark_mode));
-  }
-}

dev/integration_tests/flutter_gallery/windows/runner/win32_window.h

@@ -91,9 +91,6 @@ class Win32Window {
   // Retrieves a class instance pointer for |window|
   static Win32Window* GetThisFromHandle(HWND const window) noexcept;
 
-  // Update the window frame's theme to match the system theme.
-  static void UpdateTheme(HWND const window);
-
   bool quit_on_close_ = false;
 
   // window handle for top level window.

dev/integration_tests/windows_startup_test/lib/main.dart

@@ -5,10 +5,9 @@
 import 'dart:async';
 import 'dart:ui' as ui;
 
+import 'package:flutter/services.dart';
 import 'package:flutter_driver/driver_extension.dart';
 
-import 'windows.dart';
-
 void drawHelloWorld() {
   final ui.ParagraphStyle style = ui.ParagraphStyle();
   final ui.ParagraphBuilder paragraphBuilder = ui.ParagraphBuilder(style)
@@ -31,38 +30,33 @@ void drawHelloWorld() {
 }
 
 void main() async {
-  // Create a completer to send the window visibility result back to the
-  // integration test.
-  final Completer<String> visibilityCompleter = Completer<String>();
-  enableFlutterDriverExtension(handler: (String? message) async {
-    if (message == 'verifyWindowVisibility') {
-      return visibilityCompleter.future;
-    } else if (message == 'verifyTheme') {
-      final bool app = await isAppDarkModeEnabled();
-      final bool system = await isSystemDarkModeEnabled();
-
-      return (app == system)
-        ? 'success'
-        : 'error: app dark mode ($app) does not match system dark mode ($system)';
-    }
-
-    throw 'Unrecognized message: $message';
-  });
+  // Create a completer to send the result back to the integration test.
+  final Completer<String> completer = Completer<String>();
+  enableFlutterDriverExtension(handler: (String? message) => completer.future);
 
   try {
-    if (await isWindowVisible()) {
+    const MethodChannel methodChannel =
+        MethodChannel('tests.flutter.dev/windows_startup_test');
+
+    final bool? visible = await methodChannel.invokeMethod('isWindowVisible');
+    if (visible == null || visible == true) {
       throw 'Window should be hidden at startup';
     }
 
     bool firstFrame = true;
     ui.PlatformDispatcher.instance.onBeginFrame = (Duration duration) async {
-      if (await isWindowVisible()) {
+      final bool? visible = await methodChannel.invokeMethod('isWindowVisible');
+      if (visible == null) {
+        throw 'Method channel unavailable';
+      }
+
+      if (visible == true) {
         if (firstFrame) {
           throw 'Window should be hidden on first frame';
         }
 
-        if (!visibilityCompleter.isCompleted) {
-          visibilityCompleter.complete('success');
+        if (!completer.isCompleted) {
+          completer.complete('success');
         }
       }
 
@@ -74,7 +68,7 @@ void main() async {
 
     ui.PlatformDispatcher.instance.scheduleFrame();
   } catch (e) {
-    visibilityCompleter.completeError(e);
+    completer.completeError(e);
     rethrow;
   }
 }

dev/integration_tests/windows_startup_test/lib/windows.dart

-// Copyright 2014 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-import 'package:flutter/services.dart';
-
-const MethodChannel _kMethodChannel =
-  MethodChannel('tests.flutter.dev/windows_startup_test');
-
-/// Returns true if the application's window is visible.
-Future<bool> isWindowVisible() async {
-  final bool? visible = await _kMethodChannel.invokeMethod<bool?>('isWindowVisible');
-  if (visible == null) {
-    throw 'Method channel unavailable';
-  }
-
-  return visible;
-}
-
-/// Returns true if the app's dark mode is enabled.
-Future<bool> isAppDarkModeEnabled() async {
-  final bool? enabled = await _kMethodChannel.invokeMethod<bool?>('isAppDarkModeEnabled');
-  if (enabled == null) {
-    throw 'Method channel unavailable';
-  }
-
-  return enabled;
-}
-
-/// Returns true if the operating system dark mode setting is enabled.
-Future<bool> isSystemDarkModeEnabled() async {
-  final bool? enabled = await _kMethodChannel.invokeMethod<bool?>('isSystemDarkModeEnabled');
-  if (enabled == null) {
-    throw 'Method channel unavailable';
-  }
-
-  return enabled;
-}

dev/integration_tests/windows_startup_test/test_driver/main_test.dart

@@ -8,16 +8,7 @@ import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
 void main() {
   test('Windows app starts and draws frame', () async {
     final FlutterDriver driver = await FlutterDriver.connect(printCommunication: true);
-    final String result = await driver.requestData('verifyWindowVisibility');
-
-    expect(result, equals('success'));
-
-    await driver.close();
-  }, timeout: Timeout.none);
-
-  test('Windows app theme matches system theme', () async {
-    final FlutterDriver driver = await FlutterDriver.connect(printCommunication: true);
-    final String result = await driver.requestData('verifyTheme');
+    final String result = await driver.requestData(null);
 
     expect(result, equals('success'));
 

dev/integration_tests/windows_startup_test/windows/runner/CMakeLists.txt

@@ -33,7 +33,6 @@ target_compile_definitions(${BINARY_NAME} PRIVATE "NOMINMAX")
 # Add dependency libraries and include directories. Add any application-specific
 # dependencies here.
 target_link_libraries(${BINARY_NAME} PRIVATE flutter flutter_wrapper_app)
-target_link_libraries(${BINARY_NAME} PRIVATE "dwmapi.lib")
 target_include_directories(${BINARY_NAME} PRIVATE "${CMAKE_SOURCE_DIR}")
 
 # Run the Flutter tool portions of the build. This must not be removed.

dev/integration_tests/windows_startup_test/windows/runner/flutter_window.cpp

@@ -7,25 +7,11 @@
 #include <optional>
 #include <mutex>
 
-#include <dwmapi.h>
 #include <flutter/method_channel.h>
 #include <flutter/standard_method_codec.h>
 
 #include "flutter/generated_plugin_registrant.h"
 
-/// Window attribute that enables dark mode window decorations.
-///
-/// Redefined in case the developer's machine has a Windows SDK older than
-/// version 10.0.22000.0.
-/// See: https://docs.microsoft.com/windows/win32/api/dwmapi/ne-dwmapi-dwmwindowattribute
-#ifndef DWMWA_USE_IMMERSIVE_DARK_MODE
-#define DWMWA_USE_IMMERSIVE_DARK_MODE 20
-#endif
-
-constexpr const wchar_t kGetPreferredBrightnessRegKey[] =
-L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize";
-constexpr const wchar_t kGetPreferredBrightnessRegValue[] = L"AppsUseLightTheme";
-
 FlutterWindow::FlutterWindow(const flutter::DartProject& project)
     : project_(project) {}
 
@@ -64,38 +50,11 @@ bool FlutterWindow::OnCreate() {
       &flutter::StandardMethodCodec::GetInstance());
 
   channel.SetMethodCallHandler(
-    [&](const flutter::MethodCall<>& call,
+    [](const flutter::MethodCall<>& call,
        std::unique_ptr<flutter::MethodResult<>> result) {
-       std::string method = call.method_name();
-
-      if (method == "isWindowVisible") {
-        std::scoped_lock lock(visible_mutex);
+      std::scoped_lock lock(visible_mutex);
+      if (call.method_name() == "isWindowVisible") {
         result->Success(visible);
-      } else if (method == "isAppDarkModeEnabled") {
-        BOOL enabled;
-        HRESULT hr = DwmGetWindowAttribute(GetHandle(),
-                                           DWMWA_USE_IMMERSIVE_DARK_MODE,
-                                           &enabled, sizeof(enabled));
-        if (SUCCEEDED(hr)) {
-          result->Success((bool)enabled);
-        } else {
-          result->Error("error", "Received result handle " + hr);
-        }
-      } else if (method == "isSystemDarkModeEnabled") {
-        DWORD data;
-        DWORD data_size = sizeof(data);
-        LONG status = RegGetValue(HKEY_CURRENT_USER,
-                                  kGetPreferredBrightnessRegKey,
-                                  kGetPreferredBrightnessRegValue,
-                                  RRF_RT_REG_DWORD, nullptr, &data, &data_size);
-
-        if (status == ERROR_SUCCESS) {
-          // Preferred brightness is 0 if dark mode is enabled,
-          // otherwise non-zero.
-          result->Success(data == 0);
-        } else {
-          result->Error("error", "Received status " + status);
-        }
       } else {
         result->NotImplemented();
       }

dev/integration_tests/windows_startup_test/windows/runner/win32_window.cpp

@@ -4,28 +4,14 @@
 
 #include "win32_window.h"
 
-#include <dwmapi.h>
 #include <flutter_windows.h>
 
 #include "resource.h"
 
 namespace {
 
-/// Window attribute that enables dark mode window decorations.
-///
-/// Redefined in case the developer's machine has a Windows SDK older than
-/// version 10.0.22000.0.
-/// See: https://docs.microsoft.com/windows/win32/api/dwmapi/ne-dwmapi-dwmwindowattribute
-#ifndef DWMWA_USE_IMMERSIVE_DARK_MODE
-#define DWMWA_USE_IMMERSIVE_DARK_MODE 20
-#endif
-
 constexpr const wchar_t kWindowClassName[] = L"FLUTTER_RUNNER_WIN32_WINDOW";
 
-constexpr const wchar_t kGetPreferredBrightnessRegKey[] =
-  L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize";
-constexpr const wchar_t kGetPreferredBrightnessRegValue[] = L"AppsUseLightTheme";
-
 // The number of Win32Window objects that currently exist.
 static int g_active_window_count = 0;
 
@@ -144,8 +130,6 @@ bool Win32Window::Create(const std::wstring& title,
     return false;
   }
 
-  UpdateTheme(window);
-
   return OnCreate();
 }
 
@@ -212,10 +196,6 @@ Win32Window::MessageHandler(HWND hwnd,
         SetFocus(child_content_);
       }
       return 0;
-
-    case WM_DWMCOLORIZATIONCOLORCHANGED:
-      UpdateTheme(hwnd);
-      return 0;
   }
 
   return DefWindowProc(window_handle_, message, wparam, lparam);
@@ -271,17 +251,3 @@ bool Win32Window::OnCreate() {
 void Win32Window::OnDestroy() {
   // No-op; provided for subclasses.
 }
-
-void Win32Window::UpdateTheme(HWND const window) {
-  DWORD light_mode;
-  DWORD light_mode_size = sizeof(light_mode);
-  LONG result = RegGetValue(HKEY_CURRENT_USER, kGetPreferredBrightnessRegKey,
-                            kGetPreferredBrightnessRegValue, RRF_RT_REG_DWORD,
-                            nullptr, &light_mode, &light_mode_size);
-
-  if (result == ERROR_SUCCESS) {
-    BOOL enable_dark_mode = light_mode == 0;
-    DwmSetWindowAttribute(window, DWMWA_USE_IMMERSIVE_DARK_MODE,
-                          &enable_dark_mode, sizeof(enable_dark_mode));
-  }
-}

dev/integration_tests/windows_startup_test/windows/runner/win32_window.h

@@ -91,9 +91,6 @@ class Win32Window {
   // Retrieves a class instance pointer for |window|
   static Win32Window* GetThisFromHandle(HWND const window) noexcept;
 
-  // Update the window frame's theme to match the system theme.
-  static void UpdateTheme(HWND const window);
-
   bool quit_on_close_ = false;
 
   // window handle for top level window.

dev/manual_tests/windows/runner/CMakeLists.txt

@@ -33,7 +33,6 @@ target_compile_definitions(${BINARY_NAME} PRIVATE "NOMINMAX")
 # Add dependency libraries and include directories. Add any application-specific
 # dependencies here.
 target_link_libraries(${BINARY_NAME} PRIVATE flutter flutter_wrapper_app)
-target_link_libraries(${BINARY_NAME} PRIVATE "dwmapi.lib")
 target_include_directories(${BINARY_NAME} PRIVATE "${CMAKE_SOURCE_DIR}")
 
 # Run the Flutter tool portions of the build. This must not be removed.

dev/manual_tests/windows/runner/win32_window.cpp

@@ -4,28 +4,14 @@
 
 #include "win32_window.h"
 
-#include <dwmapi.h>
 #include <flutter_windows.h>
 
 #include "resource.h"
 
 namespace {
 
-/// Window attribute that enables dark mode window decorations.
-///
-/// Redefined in case the developer's machine has a Windows SDK older than
-/// version 10.0.22000.0.
-/// See: https://docs.microsoft.com/windows/win32/api/dwmapi/ne-dwmapi-dwmwindowattribute
-#ifndef DWMWA_USE_IMMERSIVE_DARK_MODE
-#define DWMWA_USE_IMMERSIVE_DARK_MODE 20
-#endif
-
 constexpr const wchar_t kWindowClassName[] = L"FLUTTER_RUNNER_WIN32_WINDOW";
 
-constexpr const wchar_t kGetPreferredBrightnessRegKey[] =
-  L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize";
-constexpr const wchar_t kGetPreferredBrightnessRegValue[] = L"AppsUseLightTheme";
-
 // The number of Win32Window objects that currently exist.
 static int g_active_window_count = 0;
 
@@ -144,8 +130,6 @@ bool Win32Window::Create(const std::wstring& title,
     return false;
   }
 
-  UpdateTheme(window);
-
   return OnCreate();
 }
 
@@ -212,10 +196,6 @@ Win32Window::MessageHandler(HWND hwnd,
         SetFocus(child_content_);
       }
       return 0;
-
-    case WM_DWMCOLORIZATIONCOLORCHANGED:
-      UpdateTheme(hwnd);
-      return 0;
   }
 
   return DefWindowProc(window_handle_, message, wparam, lparam);
@@ -271,17 +251,3 @@ bool Win32Window::OnCreate() {
 void Win32Window::OnDestroy() {
   // No-op; provided for subclasses.
 }
-
-void Win32Window::UpdateTheme(HWND const window) {
-  DWORD light_mode;
-  DWORD light_mode_size = sizeof(light_mode);
-  LONG result = RegGetValue(HKEY_CURRENT_USER, kGetPreferredBrightnessRegKey,
-                            kGetPreferredBrightnessRegValue, RRF_RT_REG_DWORD,
-                            nullptr, &light_mode, &light_mode_size);
-
-  if (result == ERROR_SUCCESS) {
-    BOOL enable_dark_mode = light_mode == 0;
-    DwmSetWindowAttribute(window, DWMWA_USE_IMMERSIVE_DARK_MODE,
-                          &enable_dark_mode, sizeof(enable_dark_mode));
-  }
-}

dev/manual_tests/windows/runner/win32_window.h

@@ -91,9 +91,6 @@ class Win32Window {
   // Retrieves a class instance pointer for |window|
   static Win32Window* GetThisFromHandle(HWND const window) noexcept;
 
-  // Update the window frame's theme to match the system theme.
-  static void UpdateTheme(HWND const window);
-
   bool quit_on_close_ = false;
 
   // window handle for top level window.

examples/hello_world/windows/runner/CMakeLists.txt

@@ -33,7 +33,6 @@ target_compile_definitions(${BINARY_NAME} PRIVATE "NOMINMAX")
 # Add dependency libraries and include directories. Add any application-specific
 # dependencies here.
 target_link_libraries(${BINARY_NAME} PRIVATE flutter flutter_wrapper_app)
-target_link_libraries(${BINARY_NAME} PRIVATE "dwmapi.lib")
 target_include_directories(${BINARY_NAME} PRIVATE "${CMAKE_SOURCE_DIR}")
 
 # Run the Flutter tool portions of the build. This must not be removed.

examples/hello_world/windows/runner/win32_window.cpp

@@ -4,28 +4,14 @@
 
 #include "win32_window.h"
 
-#include <dwmapi.h>
 #include <flutter_windows.h>
 
 #include "resource.h"
 
 namespace {
 
-/// Window attribute that enables dark mode window decorations.
-///
-/// Redefined in case the developer's machine has a Windows SDK older than
-/// version 10.0.22000.0.
-/// See: https://docs.microsoft.com/windows/win32/api/dwmapi/ne-dwmapi-dwmwindowattribute
-#ifndef DWMWA_USE_IMMERSIVE_DARK_MODE
-#define DWMWA_USE_IMMERSIVE_DARK_MODE 20
-#endif
-
 constexpr const wchar_t kWindowClassName[] = L"FLUTTER_RUNNER_WIN32_WINDOW";
 
-constexpr const wchar_t kGetPreferredBrightnessRegKey[] =
-  L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize";
-constexpr const wchar_t kGetPreferredBrightnessRegValue[] = L"AppsUseLightTheme";
-
 // The number of Win32Window objects that currently exist.
 static int g_active_window_count = 0;
 
@@ -144,8 +130,6 @@ bool Win32Window::Create(const std::wstring& title,
     return false;
   }
 
-  UpdateTheme(window);
-
   return OnCreate();
 }
 
@@ -212,10 +196,6 @@ Win32Window::MessageHandler(HWND hwnd,
         SetFocus(child_content_);
       }
       return 0;
-
-    case WM_DWMCOLORIZATIONCOLORCHANGED:
-      UpdateTheme(hwnd);
-      return 0;
   }
 
   return DefWindowProc(window_handle_, message, wparam, lparam);
@@ -271,17 +251,3 @@ bool Win32Window::OnCreate() {
 void Win32Window::OnDestroy() {
   // No-op; provided for subclasses.
 }
-
-void Win32Window::UpdateTheme(HWND const window) {
-  DWORD light_mode;
-  DWORD light_mode_size = sizeof(light_mode);
-  LONG result = RegGetValue(HKEY_CURRENT_USER, kGetPreferredBrightnessRegKey,
-                            kGetPreferredBrightnessRegValue, RRF_RT_REG_DWORD,
-                            nullptr, &light_mode, &light_mode_size);
-
-  if (result == ERROR_SUCCESS) {
-    BOOL enable_dark_mode = light_mode == 0;
-    DwmSetWindowAttribute(window, DWMWA_USE_IMMERSIVE_DARK_MODE,
-                          &enable_dark_mode, sizeof(enable_dark_mode));
-  }
-}

examples/hello_world/windows/runner/win32_window.h

@@ -91,9 +91,6 @@ class Win32Window {
   // Retrieves a class instance pointer for |window|
   static Win32Window* GetThisFromHandle(HWND const window) noexcept;
 
-  // Update the window frame's theme to match the system theme.
-  static void UpdateTheme(HWND const window);
-
   bool quit_on_close_ = false;
 
   // window handle for top level window.

examples/platform_channel/windows/runner/CMakeLists.txt

@@ -33,7 +33,6 @@ target_compile_definitions(${BINARY_NAME} PRIVATE "NOMINMAX")
 # Add dependency libraries and include directories. Add any application-specific
 # dependencies here.
 target_link_libraries(${BINARY_NAME} PRIVATE flutter flutter_wrapper_app)
-target_link_libraries(${BINARY_NAME} PRIVATE "dwmapi.lib")
 target_include_directories(${BINARY_NAME} PRIVATE "${CMAKE_SOURCE_DIR}")
 
 # Run the Flutter tool portions of the build. This must not be removed.

examples/platform_channel/windows/runner/win32_window.cpp

@@ -4,28 +4,14 @@
 
 #include "win32_window.h"
 
-#include <dwmapi.h>
 #include <flutter_windows.h>
 
 #include "resource.h"
 
 namespace {
 
-/// Window attribute that enables dark mode window decorations.
-///
-/// Redefined in case the developer's machine has a Windows SDK older than
-/// version 10.0.22000.0.
-/// See: https://docs.microsoft.com/windows/win32/api/dwmapi/ne-dwmapi-dwmwindowattribute
-#ifndef DWMWA_USE_IMMERSIVE_DARK_MODE
-#define DWMWA_USE_IMMERSIVE_DARK_MODE 20
-#endif
-
 constexpr const wchar_t kWindowClassName[] = L"FLUTTER_RUNNER_WIN32_WINDOW";
 
-constexpr const wchar_t kGetPreferredBrightnessRegKey[] =
-  L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize";
-constexpr const wchar_t kGetPreferredBrightnessRegValue[] = L"AppsUseLightTheme";
-
 // The number of Win32Window objects that currently exist.
 static int g_active_window_count = 0;
 
@@ -95,8 +81,6 @@ const wchar_t* WindowClassRegistrar::GetWindowClass() {
     window_class.cbClsExtra = 0;
     window_class.cbWndExtra = 0;
     window_class.hInstance = GetModuleHandle(nullptr);
-    window_class.hIcon =
-        LoadIcon(window_class.hInstance, MAKEINTRESOURCE(IDI_APP_ICON));
     window_class.hbrBackground = 0;
     window_class.lpszMenuName = nullptr;
     window_class.lpfnWndProc = Win32Window::WndProc;
@@ -111,9 +95,7 @@ void WindowClassRegistrar::UnregisterWindowClass() {
   class_registered_ = false;
 }
 
-Win32Window::Win32Window() {
-  ++g_active_window_count;
-}
+Win32Window::Win32Window() { ++g_active_window_count; }
 
 Win32Window::~Win32Window() {
   --g_active_window_count;
@@ -144,8 +126,6 @@ bool Win32Window::Create(const std::wstring& title,
     return false;
   }
 
-  UpdateTheme(window);
-
   return OnCreate();
 }
 
@@ -154,8 +134,7 @@ bool Win32Window::Show() {
 }
 
 // static
-LRESULT CALLBACK Win32Window::WndProc(HWND const window,
-                                      UINT const message,
+LRESULT CALLBACK Win32Window::WndProc(HWND const window, UINT const message,
                                       WPARAM const wparam,
                                       LPARAM const lparam) noexcept {
   if (message == WM_NCCREATE) {
@@ -174,9 +153,7 @@ LRESULT CALLBACK Win32Window::WndProc(HWND const window,
 }
 
 LRESULT
-Win32Window::MessageHandler(HWND hwnd,
-                            UINT const message,
-                            WPARAM const wparam,
+Win32Window::MessageHandler(HWND hwnd, UINT const message, WPARAM const wparam,
                             LPARAM const lparam) noexcept {
   switch (message) {
     case WM_DESTROY:
@@ -212,10 +189,6 @@ Win32Window::MessageHandler(HWND hwnd,
         SetFocus(child_content_);
       }
       return 0;
-
-    case WM_DWMCOLORIZATIONCOLORCHANGED:
-      UpdateTheme(hwnd);
-      return 0;
   }
 
   return DefWindowProc(window_handle_, message, wparam, lparam);
@@ -255,9 +228,7 @@ RECT Win32Window::GetClientArea() {
   return frame;
 }
 
-HWND Win32Window::GetHandle() {
-  return window_handle_;
-}
+HWND Win32Window::GetHandle() { return window_handle_; }
 
 void Win32Window::SetQuitOnClose(bool quit_on_close) {
   quit_on_close_ = quit_on_close;
@@ -271,17 +242,3 @@ bool Win32Window::OnCreate() {
 void Win32Window::OnDestroy() {
   // No-op; provided for subclasses.
 }
-
-void Win32Window::UpdateTheme(HWND const window) {
-  DWORD light_mode;
-  DWORD light_mode_size = sizeof(light_mode);
-  LONG result = RegGetValue(HKEY_CURRENT_USER, kGetPreferredBrightnessRegKey,
-                            kGetPreferredBrightnessRegValue, RRF_RT_REG_DWORD,
-                            nullptr, &light_mode, &light_mode_size);
-
-  if (result == ERROR_SUCCESS) {
-    BOOL enable_dark_mode = light_mode == 0;
-    DwmSetWindowAttribute(window, DWMWA_USE_IMMERSIVE_DARK_MODE,
-                          &enable_dark_mode, sizeof(enable_dark_mode));
-  }
-}

examples/platform_channel/windows/runner/win32_window.h

@@ -63,8 +63,7 @@ class Win32Window {
   // Processes and route salient window messages for mouse handling,
   // size change and DPI. Delegates handling of these to member overloads that
   // inheriting classes can handle.
-  virtual LRESULT MessageHandler(HWND window,
-                                 UINT const message,
+  virtual LRESULT MessageHandler(HWND window, UINT const message,
                                  WPARAM const wparam,
                                  LPARAM const lparam) noexcept;
 
@@ -83,17 +82,13 @@ class Win32Window {
   // non-client DPI scaling so that the non-client area automatically
   // responsponds to changes in DPI. All other messages are handled by
   // MessageHandler.
-  static LRESULT CALLBACK WndProc(HWND const window,
-                                  UINT const message,
+  static LRESULT CALLBACK WndProc(HWND const window, UINT const message,
                                   WPARAM const wparam,
                                   LPARAM const lparam) noexcept;
 
   // Retrieves a class instance pointer for |window|
   static Win32Window* GetThisFromHandle(HWND const window) noexcept;
 
-  // Update the window frame's theme to match the system theme.
-  static void UpdateTheme(HWND const window);
-
   bool quit_on_close_ = false;
 
   // window handle for top level window.

packages/flutter_tools/templates/app_shared/windows.tmpl/runner/CMakeLists.txt

@@ -33,7 +33,6 @@ target_compile_definitions(${BINARY_NAME} PRIVATE "NOMINMAX")
 # Add dependency libraries and include directories. Add any application-specific
 # dependencies here.
 target_link_libraries(${BINARY_NAME} PRIVATE flutter flutter_wrapper_app)
-target_link_libraries(${BINARY_NAME} PRIVATE "dwmapi.lib")
 target_include_directories(${BINARY_NAME} PRIVATE "${CMAKE_SOURCE_DIR}")
 
 # Run the Flutter tool portions of the build. This must not be removed.

packages/flutter_tools/templates/app_shared/windows.tmpl/runner/win32_window.cpp

 #include "win32_window.h"
 
-#include <dwmapi.h>
 #include <flutter_windows.h>
 
 #include "resource.h"
 
 namespace {
 
-/// Window attribute that enables dark mode window decorations.
-///
-/// Redefined in case the developer's machine has a Windows SDK older than
-/// version 10.0.22000.0.
-/// See: https://docs.microsoft.com/windows/win32/api/dwmapi/ne-dwmapi-dwmwindowattribute
-#ifndef DWMWA_USE_IMMERSIVE_DARK_MODE
-#define DWMWA_USE_IMMERSIVE_DARK_MODE 20
-#endif
-
 constexpr const wchar_t kWindowClassName[] = L"FLUTTER_RUNNER_WIN32_WINDOW";
 
-constexpr const wchar_t kGetPreferredBrightnessRegKey[] =
-  L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize";
-constexpr const wchar_t kGetPreferredBrightnessRegValue[] = L"AppsUseLightTheme";
-
 // The number of Win32Window objects that currently exist.
 static int g_active_window_count = 0;
 
@@ -140,8 +126,6 @@ bool Win32Window::Create(const std::wstring& title,
     return false;
   }
 
-  UpdateTheme(window);
-
   return OnCreate();
 }
 
@@ -208,10 +192,6 @@ Win32Window::MessageHandler(HWND hwnd,
         SetFocus(child_content_);
       }
       return 0;
-
-    case WM_DWMCOLORIZATIONCOLORCHANGED:
-      UpdateTheme(hwnd);
-      return 0;
   }
 
   return DefWindowProc(window_handle_, message, wparam, lparam);
@@ -267,17 +247,3 @@ bool Win32Window::OnCreate() {
 void Win32Window::OnDestroy() {
   // No-op; provided for subclasses.
 }
-
-void Win32Window::UpdateTheme(HWND const window) {
-  DWORD light_mode;
-  DWORD light_mode_size = sizeof(light_mode);
-  LONG result = RegGetValue(HKEY_CURRENT_USER, kGetPreferredBrightnessRegKey,
-                            kGetPreferredBrightnessRegValue, RRF_RT_REG_DWORD,
-                            nullptr, &light_mode, &light_mode_size);
-
-  if (result == ERROR_SUCCESS) {
-    BOOL enable_dark_mode = light_mode == 0;
-    DwmSetWindowAttribute(window, DWMWA_USE_IMMERSIVE_DARK_MODE,
-                          &enable_dark_mode, sizeof(enable_dark_mode));
-  }
-}

packages/flutter_tools/templates/app_shared/windows.tmpl/runner/win32_window.h

@@ -87,9 +87,6 @@ class Win32Window {
   // Retrieves a class instance pointer for |window|
   static Win32Window* GetThisFromHandle(HWND const window) noexcept;
 
-  // Update the window frame's theme to match the system theme.
-  static void UpdateTheme(HWND const window);
-
   bool quit_on_close_ = false;
 
   // window handle for top level window.