Add an eviction mechanism for SDCH dictionaries.

chrome/browser/net/sdch_browsertest.cc

Index: chrome/browser/net/sdch_browsertest.cc
diff --git a/chrome/browser/net/sdch_browsertest.cc b/chrome/browser/net/sdch_browsertest.cc
index 32ca64a4da040608acf9ba8df44beaacf2c271bc..1ec8c9d321a88bd147e17cc7907d33f7645d1e51 100644
--- a/chrome/browser/net/sdch_browsertest.cc
+++ b/chrome/browser/net/sdch_browsertest.cc
@@ -610,6 +610,9 @@ class SdchBrowserTest : public InProcessBrowserTest,
   }
 
   // SdchObserver
+  void OnDictionaryUsed(net::SdchManager* manager,
+                        const std::string& server_hash) override {}
+
   void OnGetDictionary(net::SdchManager* manager,
                        const GURL& request_url,
                        const GURL& dictionary_url) override {
@@ -618,6 +621,7 @@ class SdchBrowserTest : public InProcessBrowserTest,
     DCHECK(fetch_counts_.end() != fetch_counts_.find(manager));
     ++fetch_counts_[manager];
   }
+
   void OnClearDictionaries(net::SdchManager* manager) override {}
 
   // URLFetcherDelegate