fix: add missing isComposing KeyboardEvent property (#23995)

Co-authored-by: Shelley Vohr <[email protected]>

docs/api/web-contents.md

@@ -402,6 +402,7 @@ Returns:
   * `key` String - Equivalent to [KeyboardEvent.key][keyboardevent].
   * `code` String - Equivalent to [KeyboardEvent.code][keyboardevent].
   * `isAutoRepeat` Boolean - Equivalent to [KeyboardEvent.repeat][keyboardevent].
+  * `isComposing` Boolean - Equivalent to [KeyboardEvent.isComposing][keyboardevent].
   * `shift` Boolean - Equivalent to [KeyboardEvent.shiftKey][keyboardevent].
   * `control` Boolean - Equivalent to [KeyboardEvent.controlKey][keyboardevent].
   * `alt` Boolean - Equivalent to [KeyboardEvent.altKey][keyboardevent].

shell/common/gin_converters/content_converter.cc

@@ -302,6 +302,7 @@ v8::Local<v8::Value> Converter<content::NativeWebKeyboardEvent>::ToV8(
 
   using Modifiers = blink::WebInputEvent::Modifiers;
   dict.Set("isAutoRepeat", (in.GetModifiers() & Modifiers::kIsAutoRepeat) != 0);
+  dict.Set("isComposing", (in.GetModifiers() & Modifiers::kIsComposing) != 0);
   dict.Set("shift", (in.GetModifiers() & Modifiers::kShiftKey) != 0);
   dict.Set("control", (in.GetModifiers() & Modifiers::kControlKey) != 0);
   dict.Set("alt", (in.GetModifiers() & Modifiers::kAltKey) != 0);