Bug 1183085 - Update description for nsDisplayList methods; r=roc

AppendNewToTop and AppendNewToBottom do not return
NS_ERROR_OUT_OF_MEMORY now.

--HG--
extra : commitid : 1w49sx2aF6k
extra : rebase_source : b992c3c9733dd8236aafe9e03c69a6dbe68946f9

layout/base/nsDisplayList.h

@@ -1615,8 +1615,8 @@ public:
   }
   
   /**
-   * Append a new item to the top of the list. If the item is null we return
-   * NS_ERROR_OUT_OF_MEMORY. The intended usage is AppendNewToTop(new ...);
+   * Append a new item to the top of the list. The intended usage is
+   * AppendNewToTop(new ...);
    */
   void AppendNewToTop(nsDisplayItem* aItem) {
     if (aItem) {
@@ -1625,8 +1625,8 @@ public:
   }
   
   /**
-   * Append a new item to the bottom of the list. If the item is null we return
-   * NS_ERROR_OUT_OF_MEMORY. The intended usage is AppendNewToBottom(new ...);
+   * Append a new item to the bottom of the list. The intended usage is
+   * AppendNewToBottom(new ...);
    */
   void AppendNewToBottom(nsDisplayItem* aItem) {
     if (aItem) {