Bug 1302470 Part 5: Fix the case where HTML buttons need to generate display item children when doing opaque hit tests. r=mattwoodrow

MozReview-Commit-ID: HwDYsnMJkM8

layout/base/nsLayoutUtils.cpp

@@ -3174,6 +3174,8 @@ nsLayoutUtils::GetFramesForArea(nsIFrame* aFrame, const nsRect& aRect,
     builder.SetDescendIntoSubdocuments(false);
   }
 
+  builder.SetHitTestShouldStopAtFirstOpaque(aFlags & ONLY_VISIBLE);
+
   builder.EnterPresShell(aFrame);
   aFrame->BuildDisplayListForStackingContext(&builder, aRect, &list);
   builder.LeavePresShell(aFrame, nullptr);
@@ -3189,7 +3191,6 @@ nsLayoutUtils::GetFramesForArea(nsIFrame* aFrame, const nsRect& aRect,
 #endif
 
   nsDisplayItem::HitTestState hitTestState;
-  builder.SetHitTestShouldStopAtFirstOpaque(aFlags & ONLY_VISIBLE);
   list.HitTest(&builder, aRect, &hitTestState, &aOutFrames);
   list.DeleteAll();
   return NS_OK;

layout/forms/nsHTMLButtonControlFrame.cpp

@@ -119,7 +119,7 @@ nsHTMLButtonControlFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
   nsDisplayListCollection set;
 
   // Do not allow the child subtree to receive events.
-  if (!isForEventDelivery) {
+  if (!isForEventDelivery || aBuilder->HitTestShouldStopAtFirstOpaque()) {
     DisplayListClipState::AutoSaveRestore clipState(aBuilder);
 
     if (ShouldClipPaintingToBorderBox()) {