Clear the float cache from placeholders that are descendants of the frame we remove. b=337883 r+sr=roc

layout/generic/nsBlockFrame.cpp

@@ -5573,10 +5573,10 @@ nsBlockFrame::RemoveFrame(nsIAtom*  aListName,
   nsresult rv = NS_OK;
 
 #ifdef NOISY_REFLOW_REASON
-    ListTag(stdout);
-    printf(": remove ");
-    nsFrame::ListTag(stdout, aOldFrame);
-    printf("\n");
+  ListTag(stdout);
+  printf(": remove ");
+  nsFrame::ListTag(stdout, aOldFrame);
+  printf("\n");
 #endif
 
   if (nsnull == aListName) {
@@ -5790,6 +5790,13 @@ found_frame:;
     nsFrame::ListTag(stdout, aDeletedFrame);
     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

@@ -501,6 +501,34 @@ 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)) {
+        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

@@ -372,6 +372,7 @@ 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