feat: add {get|set}AccentColor on Windows (#47741)

* feat: add setAccentColor on Windows

* refactor: unify GetSystemAccentColor

* refactor: remove redundant parsing

* chore: fixup documentation

* Update docs/api/browser-window.md

Co-authored-by: Will Anderson <andersonw@dropbox.com>

* Update docs/api/base-window.md

Co-authored-by: Will Anderson <andersonw@dropbox.com>

---------

Co-authored-by: Will Anderson <andersonw@dropbox.com>

shell/browser/api/electron_api_base_window.cc

@@ -1089,6 +1089,33 @@ void BaseWindow::SetAppDetails(const gin_helper::Dictionary& options) {
 bool BaseWindow::IsSnapped() const {
   return window_->IsSnapped();
 }
+
+void BaseWindow::SetAccentColor(gin_helper::Arguments* args) {
+  bool accent_color = false;
+  std::string accent_color_string;
+  if (args->GetNext(&accent_color_string)) {
+    std::optional<SkColor> maybe_color = ParseCSSColor(accent_color_string);
+    if (maybe_color.has_value()) {
+      window_->SetAccentColor(maybe_color.value());
+      window_->UpdateWindowAccentColor(window_->IsActive());
+    }
+  } else if (args->GetNext(&accent_color)) {
+    window_->SetAccentColor(accent_color);
+    window_->UpdateWindowAccentColor(window_->IsActive());
+  } else {
+    args->ThrowError(
+        "Invalid accent color value - must be a string or boolean");
+  }
+}
+
+v8::Local<v8::Value> BaseWindow::GetAccentColor() const {
+  v8::Isolate* isolate = v8::Isolate::GetCurrent();
+  auto accent_color = window_->GetAccentColor();
+
+  if (std::holds_alternative<bool>(accent_color))
+    return v8::Boolean::New(isolate, std::get<bool>(accent_color));
+  return gin::StringToV8(isolate, std::get<std::string>(accent_color));
+}
 #endif
 
 #if BUILDFLAG(IS_WIN) || BUILDFLAG(IS_LINUX)
@@ -1277,6 +1304,8 @@ void BaseWindow::BuildPrototype(v8::Isolate* isolate,
 #if BUILDFLAG(IS_WIN)
       .SetMethod("isSnapped", &BaseWindow::IsSnapped)
       .SetProperty("snapped", &BaseWindow::IsSnapped)
+      .SetMethod("setAccentColor", &BaseWindow::SetAccentColor)
+      .SetMethod("getAccentColor", &BaseWindow::GetAccentColor)
       .SetMethod("hookWindowMessage", &BaseWindow::HookWindowMessage)
       .SetMethod("isWindowMessageHooked", &BaseWindow::IsWindowMessageHooked)
       .SetMethod("unhookWindowMessage", &BaseWindow::UnhookWindowMessage)

shell/browser/api/electron_api_base_window.h

@@ -255,6 +255,8 @@ class BaseWindow : public gin_helper::TrackableObject<BaseWindow>,
   bool SetThumbnailToolTip(const std::string& tooltip);
   void SetAppDetails(const gin_helper::Dictionary& options);
   bool IsSnapped() const;
+  void SetAccentColor(gin_helper::Arguments* args);
+  v8::Local<v8::Value> GetAccentColor() const;
 #endif
 
 #if BUILDFLAG(IS_WIN) || BUILDFLAG(IS_LINUX)

shell/browser/api/electron_api_system_preferences.h

@@ -56,7 +56,7 @@ class SystemPreferences final
   const char* GetTypeName() override;
 
 #if BUILDFLAG(IS_WIN) || BUILDFLAG(IS_MAC)
-  std::string GetAccentColor();
+  static std::string GetAccentColor();
   std::string GetColor(gin_helper::ErrorThrower thrower,
                        const std::string& color);
   std::string GetMediaAccessStatus(gin_helper::ErrorThrower thrower,

shell/browser/api/electron_api_system_preferences_win.cc

@@ -5,7 +5,6 @@
 #include <iomanip>
 #include <string_view>
 
-#include <dwmapi.h>
 #include <windows.devices.enumeration.h>
 #include <wrl/client.h>
 
@@ -84,14 +83,12 @@ std::string hexColorDWORDToRGBA(DWORD color) {
 }
 
 std::string SystemPreferences::GetAccentColor() {
-  DWORD color = 0;
-  BOOL opaque = FALSE;
+  std::optional<DWORD> color = GetSystemAccentColor();
 
-  if (FAILED(DwmGetColorizationColor(&color, &opaque))) {
+  if (!color.has_value())
     return "";
-  }
 
-  return hexColorDWORDToRGBA(color);
+  return hexColorDWORDToRGBA(color.value());
 }
 
 std::string SystemPreferences::GetColor(gin_helper::ErrorThrower thrower,

shell/browser/native_window.h

@@ -347,6 +347,10 @@ class NativeWindow : public base::SupportsUserData,
 
 #if BUILDFLAG(IS_WIN)
   void NotifyWindowMessage(UINT message, WPARAM w_param, LPARAM l_param);
+  virtual void SetAccentColor(
+      std::variant<std::monostate, bool, SkColor> accent_color) = 0;
+  virtual std::variant<bool, std::string> GetAccentColor() const = 0;
+  virtual void UpdateWindowAccentColor(bool active) = 0;
 #endif
 
   void AddObserver(NativeWindowObserver* obs) { observers_.AddObserver(obs); }

shell/browser/native_window_views.cc

@@ -26,6 +26,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "content/public/browser/desktop_media_id.h"
 #include "content/public/common/color_parser.h"
+#include "shell/browser/api/electron_api_system_preferences.h"
 #include "shell/browser/api/electron_api_web_contents.h"
 #include "shell/browser/ui/inspectable_web_contents_view.h"
 #include "shell/browser/ui/views/root_view.h"

shell/browser/native_window_views.h

@@ -176,6 +176,10 @@ class NativeWindowViews : public NativeWindow,
 #endif
 
 #if BUILDFLAG(IS_WIN)
+  void SetAccentColor(
+      std::variant<std::monostate, bool, SkColor> accent_color) override;
+  std::variant<bool, std::string> GetAccentColor() const override;
+  void UpdateWindowAccentColor(bool active) override;
   TaskbarHost& taskbar_host() { return taskbar_host_; }
   void UpdateThickFrame();
   void SetLayered();
@@ -223,7 +227,6 @@ class NativeWindowViews : public NativeWindow,
   void ResetWindowControls();
   void SetRoundedCorners(bool rounded);
   void SetForwardMouseMessages(bool forward);
-  void UpdateWindowAccentColor(bool active);
   static LRESULT CALLBACK SubclassProc(HWND hwnd,
                                        UINT msg,
                                        WPARAM w_param,

shell/browser/native_window_views_win.cc

@@ -16,7 +16,9 @@
 #include "shell/browser/native_window_views.h"
 #include "shell/browser/ui/views/root_view.h"
 #include "shell/browser/ui/views/win_frame_view.h"
+#include "shell/common/color_util.h"
 #include "shell/common/electron_constants.h"
+#include "skia/ext/skia_utils_win.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
 #include "ui/gfx/geometry/resize_utils.h"
@@ -46,21 +48,6 @@ void SetWindowBorderAndCaptionColor(HWND hwnd, COLORREF color) {
     LOG(WARNING) << "Failed to set border color";
 }
 
-std::optional<DWORD> GetAccentColor() {
-  base::win::RegKey key;
-  if (key.Open(HKEY_CURRENT_USER, L"SOFTWARE\\Microsoft\\Windows\\DWM",
-               KEY_READ) != ERROR_SUCCESS) {
-    return std::nullopt;
-  }
-
-  DWORD accent_color = 0;
-  if (key.ReadValueDW(L"AccentColor", &accent_color) != ERROR_SUCCESS) {
-    return std::nullopt;
-  }
-
-  return accent_color;
-}
-
 bool IsAccentColorOnTitleBarsEnabled() {
   base::win::RegKey key;
   if (key.Open(HKEY_CURRENT_USER, L"SOFTWARE\\Microsoft\\Windows\\DWM",
@@ -594,7 +581,7 @@ void NativeWindowViews::UpdateWindowAccentColor(bool active) {
 
   // Use system accent color as fallback if no explicit color was set.
   if (!border_color.has_value() && should_apply_accent) {
-    std::optional<DWORD> system_accent_color = GetAccentColor();
+    std::optional<DWORD> system_accent_color = GetSystemAccentColor();
     if (system_accent_color.has_value()) {
       border_color = RGB(GetRValue(system_accent_color.value()),
                          GetGValue(system_accent_color.value()),
@@ -606,6 +593,39 @@ void NativeWindowViews::UpdateWindowAccentColor(bool active) {
   SetWindowBorderAndCaptionColor(GetAcceleratedWidget(), final_color);
 }
 
+void NativeWindowViews::SetAccentColor(
+    std::variant<std::monostate, bool, SkColor> accent_color) {
+  accent_color_ = accent_color;
+}
+
+/*
+ * Returns the window's accent color, per the following heuristic:
+ *
+ * - If |accent_color_| is an SkColor, return that color as a hex string.
+ * - If |accent_color_| is true, return the system accent color as a hex string.
+ * - If |accent_color_| is false, return false.
+ * - Otherwise, return the system accent color as a hex string.
+ */
+std::variant<bool, std::string> NativeWindowViews::GetAccentColor() const {
+  std::optional<DWORD> system_color = GetSystemAccentColor();
+
+  if (std::holds_alternative<SkColor>(accent_color_)) {
+    return ToRGBHex(std::get<SkColor>(accent_color_));
+  } else if (std::holds_alternative<bool>(accent_color_)) {
+    if (std::get<bool>(accent_color_)) {
+      if (!system_color.has_value())
+        return false;
+      return ToRGBHex(skia::COLORREFToSkColor(system_color.value()));
+    } else {
+      return false;
+    }
+  } else {
+    if (!system_color.has_value())
+      return false;
+    return ToRGBHex(skia::COLORREFToSkColor(system_color.value()));
+  }
+}
+
 void NativeWindowViews::ResetWindowControls() {
   // If a given window was minimized and has since been
   // unminimized (restored/maximized), ensure the WCO buttons