Bug 1415672 - Don't invalidate the entire frame tree when we're marking a specific frame as being modified. r=miko

--HG--
extra : rebase_source : 7ec5936718e52803bcdf6f1edf435b8247c5107d

layout/painting/nsDisplayList.h

@@ -1607,7 +1607,6 @@ public:
     if (!aFrame->IsFrameModified()) {
       mModifiedFramesDuringBuilding.AppendElement(aFrame);
       aFrame->SetFrameIsModified(true);
-      mInInvalidSubtree = true;
       return true;
     }
     return false;