Pin dictionaries from being deleted while request is outstanding.

net/filter/sdch_filter.h

Index: net/filter/sdch_filter.h
diff --git a/net/filter/sdch_filter.h b/net/filter/sdch_filter.h
index a1a6607ad9293a447303bac885cee9fb776ac533..44e785fa6eef2e41675e11256809eb3df7039199 100644
--- a/net/filter/sdch_filter.h
+++ b/net/filter/sdch_filter.h
@@ -92,10 +92,10 @@ class NET_EXPORT_PRIVATE SdchFilter : public Filter {
   // attempted.
   bool dictionary_hash_is_plausible_;
 
-  // We hold an in-memory copy of the dictionary during the entire decoding, as
-  // it is used directly by the VC-DIFF decoding system.
-  // That char* data is part of the dictionary_ we hold a reference to.
-  scoped_refptr<SdchManager::Dictionary> dictionary_;
+  // Validity of this pointer is guaranteed by either the FilterContext holding
+  // a containing SdchManager::DictionarySet, or this object holding a
+  // container in |unexpected_dictionary_handle_| below.
+  const SdchManager::Dictionary *dictionary_;
 
   // We keep a copy of the URLRequestContext for use in the destructor, (at
   // which point GetURLRequestContext() will likely return null because of
@@ -129,6 +129,11 @@ class NET_EXPORT_PRIVATE SdchFilter : public Filter {
   // by checking within this mime type (we may do a meta-refresh via html).
   std::string mime_type_;
 
+  // If the response was encoded with a dictionary different than those
+  // advertised (e.g. a cached response using an old dictionary), this
+  // variable preserves that dictionary from deletion during decoding.
+  scoped_ptr<SdchManager::DictionarySet> unexpected_dictionary_handle_;
+
   DISALLOW_COPY_AND_ASSIGN(SdchFilter);
 };