Bug 1298205 - Fix ServoRestyleManager.cpp includes. r=heycam

MozReview-Commit-ID: IhXCuG7V7gL

--HG--
extra : rebase_source : 37a2401266ee6ae1942a2b5014a38cbfb3d6c9ab

layout/base/ServoRestyleManager.cpp

@@ -8,6 +8,7 @@
 #include "mozilla/ServoStyleSet.h"
 #include "mozilla/dom/ChildIterator.h"
 #include "nsContentUtils.h"
+#include "nsPrintfCString.h"
 #include "nsStyleChangeList.h"
 
 using namespace mozilla::dom;