fix: CHECK when adding view as its own child (#42067)

shell/browser/api/electron_api_view.cc

@@ -189,6 +189,14 @@ void View::AddChildViewAt(gin::Handle<View> child,
   // has a View, possibly a wrapper view around the underlying platform View.
   if (!view_)
     return;
+
+  // This will CHECK and crash in View::AddChildViewAtImpl if not handled here.
+  if (view_ == child->view()) {
+    gin_helper::ErrorThrower(isolate()).ThrowError(
+        "A view cannot be added as its own child");
+    return;
+  }
+
   size_t index =
       std::min(child_views_.size(), maybe_index.value_or(child_views_.size()));
   child_views_.emplace(child_views_.begin() + index,     // index

spec/api-view-spec.ts

@@ -1,3 +1,4 @@
+import { expect } from 'chai';
 import { closeWindow } from './lib/window-helpers';
 import { BaseWindow, View } from 'electron/main';
 
@@ -10,6 +11,15 @@ describe('View', () => {
 
   it('can be used as content view', () => {
     w = new BaseWindow({ show: false });
-    w.setContentView(new View());
+    const v = new View();
+    w.setContentView(v);
+    expect(w.contentView).to.equal(v);
+  });
+
+  it('will throw when added as a child to itself', () => {
+    w = new BaseWindow({ show: false });
+    expect(() => {
+      w.contentView.addChildView(w.contentView);
+    }).to.throw('A view cannot be added as its own child');
   });
 });