feat: add BrowserWindow.isTabletMode API (#25209)

docs/api/browser-window.md

@@ -1346,6 +1346,17 @@ Enters or leaves kiosk mode.
 
 Returns `Boolean` - Whether the window is in kiosk mode.
 
+#### `win.isTabletMode()` _Windows_
+
+Returns `Boolean` - Whether the window is in Windows 10 tablet mode.
+
+Since Windows 10 users can [use their PC as tablet](https://support.microsoft.com/en-us/help/17210/windows-10-use-your-pc-like-a-tablet),
+under this mode apps can choose to optimize their UI for tablets, such as
+enlarging the titlebar and hiding titlebar buttons.
+
+This API returns whether the window is in tablet mode, and the `resize` event
+can be be used to listen to changes to tablet mode.
+
 #### `win.getMediaSourceId()`
 
 Returns `String` - Window id in the format of DesktopCapturerSource's id. For example "window:1234:0".

shell/browser/api/electron_api_base_window.cc

@@ -622,6 +622,10 @@ bool BaseWindow::IsKiosk() {
   return window_->IsKiosk();
 }
 
+bool BaseWindow::IsTabletMode() const {
+  return window_->IsTabletMode();
+}
+
 void BaseWindow::SetBackgroundColor(const std::string& color_name) {
   SkColor color = ParseHexColor(color_name);
   window_->SetBackgroundColor(color);
@@ -1160,6 +1164,7 @@ void BaseWindow::BuildPrototype(v8::Isolate* isolate,
       .SetMethod("isSimpleFullScreen", &BaseWindow::IsSimpleFullScreen)
       .SetMethod("setKiosk", &BaseWindow::SetKiosk)
       .SetMethod("isKiosk", &BaseWindow::IsKiosk)
+      .SetMethod("isTabletMode", &BaseWindow::IsTabletMode)
       .SetMethod("setBackgroundColor", &BaseWindow::SetBackgroundColor)
       .SetMethod("getBackgroundColor", &BaseWindow::GetBackgroundColor)
       .SetMethod("setHasShadow", &BaseWindow::SetHasShadow)

shell/browser/api/electron_api_base_window.h

@@ -152,6 +152,7 @@ class BaseWindow : public gin_helper::TrackableObject<BaseWindow>,
   bool IsSimpleFullScreen();
   void SetKiosk(bool kiosk);
   bool IsKiosk();
+  bool IsTabletMode() const;
   virtual void SetBackgroundColor(const std::string& color_name);
   std::string GetBackgroundColor();
   void SetHasShadow(bool has_shadow);

shell/browser/native_window.cc

@@ -310,6 +310,10 @@ double NativeWindow::GetSheetOffsetY() {
   return sheet_offset_y_;
 }
 
+bool NativeWindow::IsTabletMode() const {
+  return false;
+}
+
 void NativeWindow::SetRepresentedFilename(const std::string& filename) {}
 
 std::string NativeWindow::GetRepresentedFilename() {

shell/browser/native_window.h

@@ -148,6 +148,7 @@ class NativeWindow : public base::SupportsUserData,
   virtual bool IsSimpleFullScreen() = 0;
   virtual void SetKiosk(bool kiosk) = 0;
   virtual bool IsKiosk() = 0;
+  virtual bool IsTabletMode() const;
   virtual void SetBackgroundColor(SkColor color) = 0;
   virtual SkColor GetBackgroundColor() = 0;
   virtual void SetHasShadow(bool has_shadow) = 0;

shell/browser/native_window_views.cc

@@ -60,6 +60,7 @@
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host_linux.h"
 #include "ui/views/window/native_frame_view.h"
 #elif defined(OS_WIN)
+#include "base/win/win_util.h"
 #include "shell/browser/ui/views/win_frame_view.h"
 #include "shell/browser/ui/win/electron_desktop_native_widget_aura.h"
 #include "skia/ext/skia_utils_win.h"
@@ -901,6 +902,14 @@ bool NativeWindowViews::IsKiosk() {
   return IsFullscreen();
 }
 
+bool NativeWindowViews::IsTabletMode() const {
+#if defined(OS_WIN)
+  return base::win::IsWindows10TabletMode(GetAcceleratedWidget());
+#else
+  return false;
+#endif
+}
+
 SkColor NativeWindowViews::GetBackgroundColor() {
   return root_view_->background()->get_color();
 }

shell/browser/native_window_views.h

@@ -101,6 +101,7 @@ class NativeWindowViews : public NativeWindow,
   bool IsSimpleFullScreen() override;
   void SetKiosk(bool kiosk) override;
   bool IsKiosk() override;
+  bool IsTabletMode() const override;
   void SetBackgroundColor(SkColor color) override;
   void SetHasShadow(bool has_shadow) override;
   bool HasShadow() override;