Bug 391412: Regression in float layout causing clear to be ignored. r+sr=roc, a=dbaron

layout/generic/nsSpaceManager.cpp

@@ -879,7 +879,7 @@ nsSpaceManager::AddRectRegion(nsIFrame* aFrame, const nsRect& aUnavailableSpace)
     return NS_ERROR_OUT_OF_MEMORY;
   }
 
-  if (aUnavailableSpace.IsEmpty())
+  if (aUnavailableSpace.height <= 0)
     return NS_OK;
 
   // Allocate a band rect
@@ -930,7 +930,7 @@ nsSpaceManager::RemoveRegion(nsIFrame* aFrame)
     return NS_ERROR_INVALID_ARG;
   }
 
-  if (!frameInfo->mRect.IsEmpty()) {
+  if (frameInfo->mRect.height > 0) {
     NS_ASSERTION(!mBandList.IsEmpty(), "no bands");
     BandRect* band = mBandList.Head();
     BandRect* prevBand = nsnull;