Leave the placeholder's pointer to the out-of-flow intact because the float cache depends on it later on. b=348688 r=bzbarsky sr=roc

layout/base/nsCSSFrameConstructor.cpp

@@ -9772,7 +9772,8 @@ DoDeletingFrameSubtree(nsFrameManager* aFrameManager,
   
         // Remove the mapping from the out-of-flow frame to its placeholder.
         aFrameManager->UnregisterPlaceholderFrame((nsPlaceholderFrame*)childFrame);
-        ((nsPlaceholderFrame*)childFrame)->SetOutOfFlowFrame(nsnull);
+        // Don't SetOutOfFlowFrame(nsnull) here because the float cache depends
+        // on it when the float is removed later on, see bug 348688 comment 6.
         
         // Queue the out-of-flow frame to be destroyed only if aRemovedFrame is _not_
         // one of its ancestor frames or if it is a popup frame. 

layout/generic/nsBlockFrame.cpp

@@ -5879,12 +5879,6 @@ found_frame:;
     printf(" prevSibling=%p deletedNextContinuation=%p\n", prevSibling, deletedNextContinuation);
 #endif
 
-    if (!aDeletedFrame->IsFloatContainingBlock()) {
-      // Clear the float cache from placeholders that are descendants
-      // of aDeletedFrame (bug 337883).
-      line->RemovePlaceholderDescendantsOf(aDeletedFrame);
-    }
-
     if (aDestroyFrames) {
       aDeletedFrame->Destroy();
     } else {

layout/generic/nsLineBox.cpp

@@ -523,34 +523,6 @@ nsLineBox::RemoveFloat(nsIFrame* aFrame)
   return PR_FALSE;
 }
 
-void
-nsLineBox::RemovePlaceholderDescendantsOf(nsIFrame* aFrame)
-{
-  if (IsInline() && mInlineData) {
-    nsFloatCache* fc = mInlineData->mFloats.Head();
-    while (fc) {
-      nsIFrame* frame = fc->mPlaceholder;
-      while (frame && frame != aFrame) {
-        if (frame->IsFloatContainingBlock()) {
-          frame = nsnull;
-          break;
-        }
-        frame = frame->GetParent();
-      }
-      if (NS_UNLIKELY(frame != nsnull)) {
-        nsFloatCache* next = fc->Next();
-        mInlineData->mFloats.Remove(fc);
-        delete fc;
-        MaybeFreeData();
-        fc = next;
-      }
-      else {
-        fc = fc->Next();
-      }
-    }
-  }
-}
-
 void
 nsLineBox::SetCombinedArea(const nsRect& aCombinedArea)
 {  

layout/generic/nsLineBox.h

@@ -402,7 +402,6 @@ public:
   void FreeFloats(nsFloatCacheFreeList& aFreeList);
   void AppendFloats(nsFloatCacheFreeList& aFreeList);
   PRBool RemoveFloat(nsIFrame* aFrame);
-  void RemovePlaceholderDescendantsOf(nsIFrame* aFrame);
 
   // Combined area is the area of the line that should influence the
   // overflow area of its parent block.  The combined area should be