Revert of Resubmit: Add real file for AdNetworks DB

chrome/browser/extensions/activity_log/hashed_ad_network_database.h

Index: chrome/browser/extensions/activity_log/hashed_ad_network_database.h
diff --git a/chrome/browser/extensions/activity_log/hashed_ad_network_database.h b/chrome/browser/extensions/activity_log/hashed_ad_network_database.h
index dae28661ab20c7b8f2c872de92c51803c036d877..74deb7bc78e6bd98badabcd21343ba307f8cd932 100644
--- a/chrome/browser/extensions/activity_log/hashed_ad_network_database.h
+++ b/chrome/browser/extensions/activity_log/hashed_ad_network_database.h
@@ -23,16 +23,9 @@
       scoped_refptr<base::RefCountedStaticMemory> memory);
   virtual ~HashedAdNetworkDatabase();
 
-  bool is_valid() const { return is_valid_; }
-
  private:
   // AdNetworkDatabase implementation.
   virtual bool IsAdNetwork(const GURL& url) const OVERRIDE;
-
-  // Whether or not the database is valid, i.e., has correctly parsed the hash
-  // file. If it is not, it will always return false for IsAdNetwork(), since
-  // it cannot match against known hashes.
-  bool is_valid_;
 
   // The set of partial hashes for known ad networks.
   base::hash_set<int64> entries_;