Bug 1377648 - Fix HTMLSummaryElement::IsSummary() on removing the element

* Use inFlowFrame to check the target frame is summary and its parent is details
* Check summary frame instead of summary element on removing the summary

Tag #1375

layout/base/nsCSSFrameConstructor.cpp

@@ -9395,23 +9395,6 @@ nsCSSFrameConstructor::MaybeRecreateContainerForFrameRemoval(nsIFrame* aFrame,
     return true;
   }
 
-  if (insertionFrame &&
-      aFrame->GetParent()->GetType() == nsGkAtoms::detailsFrame) {
-    HTMLSummaryElement* summary =
-      HTMLSummaryElement::FromContent(insertionFrame->GetContent());
-
-    if (summary && summary->IsMainSummary()) {
-      // When removing a summary, we should reframe the parent details frame to
-      // ensure that another summary is used or the default summary is
-      // generated.
-      RecreateFramesForContent(aFrame->GetParent()->GetContent(),
-                               false, REMOVE_FOR_RECONSTRUCTION,
-                               aDestroyedFramesFor);
-      return true;
-    }
-  }
-
-  // Now check for possibly needing to reconstruct due to a pseudo parent
   nsIFrame* inFlowFrame =
     (aFrame->GetStateBits() & NS_FRAME_OUT_OF_FLOW) ?
       aFrame->GetPlaceholderFrame() : aFrame;
@@ -9419,6 +9402,27 @@ nsCSSFrameConstructor::MaybeRecreateContainerForFrameRemoval(nsIFrame* aFrame,
   MOZ_ASSERT(inFlowFrame == inFlowFrame->FirstContinuation(),
              "placeholder for primary frame has previous continuations?");
   nsIFrame* parent = inFlowFrame->GetParent();
+
+  if (parent && parent->GetType() == nsGkAtoms::detailsFrame) {
+    HTMLSummaryElement* summary =
+      HTMLSummaryElement::FromContent(aFrame->GetContent());
+    DetailsFrame* detailsFrame = static_cast<DetailsFrame*>(parent);
+
+    // Unlike adding summary element cases, we need to check children of the
+    // parent details frame since at this moment the summary element has been
+    // already removed from the parent details element's child list.
+    if (summary && detailsFrame->HasMainSummaryFrame(aFrame)) {
+      // When removing a summary, we should reframe the parent details frame to
+      // ensure that another summary is used or the default summary is
+      // generated.
+      RecreateFramesForContent(parent->GetContent(),
+                               false, REMOVE_FOR_RECONSTRUCTION,
+                               aDestroyedFramesFor);
+      return true;
+    }
+  }
+
+  // Now check for possibly needing to reconstruct due to a pseudo parent
   // For the case of ruby pseudo parent, effectively, only pseudo rb/rt frame
   // need to be checked here, since all other types of parent will be catched
   // by "Check ruby containers" section below.

layout/generic/DetailsFrame.cpp

@@ -129,3 +129,12 @@ DetailsFrame::AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,
     aElements.AppendElement(mDefaultSummary);
   }
 }
+
+bool
+DetailsFrame::HasMainSummaryFrame(nsIFrame* aSummaryFrame)
+{
+  nsIFrame* firstChild =
+    nsPlaceholderFrame::GetRealFrameFor(mFrames.FirstChild());
+
+  return aSummaryFrame == firstChild;
+}

layout/generic/DetailsFrame.h

@@ -54,6 +54,12 @@ public:
 
   void AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,
                                 uint32_t aFilter) override;
+  // Returns true if |aSummaryFrame| is the main summary (i.e. the first child
+  // of this details frame).
+  // This function is used when the summary element is removed from the parent
+  // details element since at that moment the summary element has been already
+  // removed from the details element children.
+  bool HasMainSummaryFrame(nsIFrame* aSummaryFrame);
 
 private:
   nsCOMPtr<nsIContent> mDefaultSummary;

layout/reftests/details-summary/reftest.list

@@ -101,3 +101,7 @@ fuzzy(1,1) == mouse-click-twice-float-details.html float-details.html # Bug 1316
 == details-before.html single-summary.html
 == open-details-after.html open-single-summary.html
 == open-details-before.html open-single-summary.html
+
+# Move summary element
+== move-float-summary-to-different-details.html move-float-summary-to-different-details-ref.html
+== move-position-absolute-summary-to-different-details.html move-position-absolute-summary-to-different-details-ref.html