Bug 1195672 - Add |nsAutoCString nsIFrame::ListTag()| for debugging. f=mtseng, r=roc

This make it easier to print a frame tag name in one debug log line.

--HG--
extra : commitid : 5bl8GhmTLQi
extra : rebase_source : f151c98dc99c33e8050b106ab8695a9053dbb3ad

layout/generic/nsIFrame.h

@@ -34,6 +34,7 @@
 #include "nsITheme.h"
 #include "nsLayoutUtils.h"
 #include "nsQueryFrame.h"
+#include "nsStringGlue.h"
 #include "nsStyleContext.h"
 #include "nsStyleStruct.h"
 
@@ -3225,6 +3226,11 @@ public:
     fputs(t.get(), out);
   }
   void ListTag(nsACString& aTo) const;
+  nsAutoCString ListTag() const {
+    nsAutoCString tag;
+    ListTag(tag);
+    return tag;
+  }
   static void ListTag(nsACString& aTo, const nsIFrame* aFrame);
   void ListGeneric(nsACString& aTo, const char* aPrefix = "", uint32_t aFlags = 0) const;
   enum {