Bug 1331380 - Remove unused kDefaultViewportSize. r=botond

MozReview-Commit-ID: 80gkw0BUErW

--HG--
extra : rebase_source : ba759cc9406cfdea2a2483ba84047e9c3291c985

dom/ipc/TabChild.cpp

@@ -151,8 +151,6 @@ NS_IMPL_ISUPPORTS(TabChildSHistoryListener,
                   nsIPartialSHistoryListener,
                   nsISupportsWeakReference)
 
-static const CSSSize kDefaultViewportSize(980, 480);
-
 static const char BEFORE_FIRST_PAINT[] = "before-first-paint";
 
 typedef nsDataHashtable<nsUint64HashKey, TabChild*> TabChildMap;