Bug 1212136 - Remove noisy warning that we don't have time to investigate properly. r=tnikkel

layout/base/nsLayoutUtils.cpp

@@ -882,7 +882,8 @@ GetDisplayPortFromMarginsData(nsIContent* aContent,
   if (nsRect* baseData = static_cast<nsRect*>(aContent->GetProperty(nsGkAtoms::DisplayPortBase))) {
     base = *baseData;
   } else {
-    NS_WARNING("Attempting to get a margins-based displayport with no base data!");
+    // In theory we shouldn't get here, but we do sometimes (see bug 1212136).
+    // Fall through for graceful handling.
   }
 
   nsIFrame* frame = aContent->GetPrimaryFrame();