Bug 729519 - Simplify DestroyOverflowList() by requiring that the list is empty. r=bzbarsky

layout/generic/nsContainerFrame.cpp

@@ -1278,7 +1278,7 @@ nsContainerFrame::StealFrame(nsPresContext* aPresContext,
       if (frameList) {
         removed = frameList->ContinueRemoveFrame(aChild);
         if (frameList->IsEmpty()) {
-          DestroyOverflowList(aPresContext, nullptr);
+          DestroyOverflowList(aPresContext);
         }
       }
     }
@@ -1325,20 +1325,6 @@ nsContainerFrame::StealFramesAfter(nsIFrame* aChild)
   return nsFrameList::EmptyList();
 }
 
-void
-nsContainerFrame::DestroyOverflowList(nsPresContext* aPresContext,
-                                      nsIFrame*      aDestructRoot)
-{
-  nsFrameList* list =
-    RemovePropTableFrames(aPresContext, OverflowProperty());
-  if (list) {
-    if (aDestructRoot)
-      list->DestroyFrom(aDestructRoot);
-    else
-      list->Destroy();
-  }
-}
-
 /*
  * Create a next-in-flow for aFrame. Will return the newly created
  * frame in aNextInFlowResult <b>if and only if</b> a new frame is

layout/generic/nsContainerFrame.h

@@ -441,12 +441,9 @@ protected:
                          const nsFrameList& aOverflowFrames);
 
   /**
-   * Destroy the overflow list and any frames that are on it.
-   * Calls DestructFrom() insead of Destruct() on the frames if
-   * aDestructRoot is non-null.
+   * Destroy the overflow list, which must be empty.
    */
-  void DestroyOverflowList(nsPresContext* aPresContext,
-                           nsIFrame*      aDestructRoot);
+  inline void DestroyOverflowList(nsPresContext* aPresContext);
 
   /**
    * Moves any frames on both the prev-in-flow's overflow list and the
@@ -678,4 +675,12 @@ nsContainerFrame::StealOverflowFrames()
   return list;
 }
 
+inline void
+nsContainerFrame::DestroyOverflowList(nsPresContext* aPresContext)
+{
+  nsFrameList* list = RemovePropTableFrames(aPresContext, OverflowProperty());
+  MOZ_ASSERT(list && list->IsEmpty());
+  delete list;
+}
+
 #endif /* nsContainerFrame_h___ */

layout/generic/nsInlineFrame.cpp

@@ -767,21 +767,20 @@ nsInlineFrame::PullOneFrame(nsPresContext* aPresContext,
 
   nsIFrame* frame = nullptr;
   nsInlineFrame* nextInFlow = irs.mNextInFlow;
-  while (nullptr != nextInFlow) {
+  while (nextInFlow) {
     frame = nextInFlow->mFrames.FirstChild();
     if (!frame) {
       // The nextInFlow's principal list has no frames, try its overflow list.
       nsFrameList* overflowFrames = nextInFlow->GetOverflowFrames();
       if (overflowFrames) {
-        frame = overflowFrames->FirstChild();
-        if (!frame->GetNextSibling()) {
+        frame = overflowFrames->RemoveFirstChild();
+        if (overflowFrames->IsEmpty()) {
           // We're stealing the only frame - delete the overflow list.
-          delete nextInFlow->StealOverflowFrames();
+          nextInFlow->DestroyOverflowList(aPresContext);
         } else {
           // We leave the remaining frames on the overflow list (rather than
           // putting them on nextInFlow's principal list) so we don't have to
           // set up the parent for them.
-          overflowFrames->RemoveFirstChild();
         }
         // ReparentFloatsForInlineChild needs it to be on a child list -
         // we remove it again below.
@@ -789,7 +788,7 @@ nsInlineFrame::PullOneFrame(nsPresContext* aPresContext,
       }
     }
 
-    if (nullptr != frame) {
+    if (frame) {
       // If our block has no next continuation, then any floats belonging to
       // the pulled frame must belong to our block already. This check ensures
       // we do no extra work in the common non-vertical-breaking case.
@@ -810,7 +809,7 @@ nsInlineFrame::PullOneFrame(nsPresContext* aPresContext,
       nsContainerFrame::ReparentFrameView(aPresContext, frame, nextInFlow, this);
       break;
     }
-    nextInFlow = (nsInlineFrame*) nextInFlow->GetNextInFlow();
+    nextInFlow = static_cast<nsInlineFrame*>(nextInFlow->GetNextInFlow());
     irs.mNextInFlow = nextInFlow;
   }