fix: segfault on webContents.fromId(xxx) (#26651)

Co-authored-by: Jeremy Rose <[email protected]>

docs/api/web-contents.md

@@ -42,7 +42,8 @@ returns `null`.
 
 * `id` Integer
 
-Returns `WebContents` - A WebContents instance with the given ID.
+Returns `WebContents` | undefined - A WebContents instance with the given ID, or
+`undefined` if there is no WebContents associated with the given ID.
 
 ## Class: WebContents
 

shell/browser/api/electron_api_web_contents.cc

@@ -3781,6 +3781,12 @@ namespace {
 using electron::api::GetAllWebContents;
 using electron::api::WebContents;
 
+gin::Handle<WebContents> WebContentsFromID(v8::Isolate* isolate, int32_t id) {
+  WebContents* contents = WebContents::FromID(id);
+  return contents ? gin::CreateHandle(isolate, contents)
+                  : gin::Handle<WebContents>();
+}
+
 std::vector<gin::Handle<WebContents>> GetAllWebContentsAsV8(
     v8::Isolate* isolate) {
   std::vector<gin::Handle<WebContents>> list;
@@ -3798,7 +3804,7 @@ void Initialize(v8::Local<v8::Object> exports,
   v8::Isolate* isolate = context->GetIsolate();
   gin_helper::Dictionary dict(isolate, exports);
   dict.Set("WebContents", WebContents::GetConstructor(context));
-  dict.SetMethod("fromId", &WebContents::FromID);
+  dict.SetMethod("fromId", &WebContentsFromID);
   dict.SetMethod("getAllWebContents", &GetAllWebContentsAsV8);
 }
 

spec-main/api-web-contents-spec.ts

@@ -42,6 +42,12 @@ describe('webContents module', () => {
     });
   });
 
+  describe('fromId()', () => {
+    it('returns undefined for an unknown id', () => {
+      expect(webContents.fromId(12345)).to.be.undefined();
+    });
+  });
+
   describe('will-prevent-unload event', function () {
     afterEach(closeAllWindows);
     it('does not emit if beforeunload returns undefined', async () => {