Bug 1752651 - Clone indeterminateness of input elements. r=smaug

Matches other browsers and makes sense.

Differential Revision: https://phabricator.services.mozilla.com/D137442

dom/html/HTMLInputElement.cpp

@@ -1130,6 +1130,8 @@ nsresult HTMLInputElement::Clone(dom::NodeInfo* aNodeInfo,
     it->mShouldInitChecked = false;
   }
 
+  it->mIndeterminate = mIndeterminate;
+
   it->DoneCreatingElement();
 
   it->SetLastValueChangeWasInteractive(mLastValueChangeWasInteractive);
@@ -1445,8 +1447,9 @@ void HTMLInputElement::SetIndeterminateInternal(bool aValue,
 
   if (aShouldInvalidate) {
     // Repaint the frame
-    nsIFrame* frame = GetPrimaryFrame();
-    if (frame) frame->InvalidateFrameSubtree();
+    if (nsIFrame* frame = GetPrimaryFrame()) {
+      frame->InvalidateFrameSubtree();
+    }
   }
 
   UpdateState(true);