[safe browsing] Remove stale BINHASH code.

chrome/browser/safe_browsing/safe_browsing_database.h

Index: chrome/browser/safe_browsing/safe_browsing_database.h
diff --git a/chrome/browser/safe_browsing/safe_browsing_database.h b/chrome/browser/safe_browsing/safe_browsing_database.h
index 2c5c7c28e8ac3320b645b157f3e4a706a71947db..912216021a7be2456033136a4525068a519e7243 100644
--- a/chrome/browser/safe_browsing/safe_browsing_database.h
+++ b/chrome/browser/safe_browsing/safe_browsing_database.h
@@ -110,10 +110,6 @@ class SafeBrowsingDatabase {
   virtual bool ContainsDownloadUrl(const std::vector<GURL>& urls,
                                    std::vector<SBPrefix>* prefix_hits) = 0;
 
-  // Returns false if |prefix| is not in Download database.
-  // This function could ONLY be accessed from creation thread.
-  virtual bool ContainsDownloadHashPrefix(const SBPrefix& prefix) = 0;
-
   // Returns false if |url| is not on the client-side phishing detection
   // whitelist.  Otherwise, this function returns true.  Note: the whitelist
   // only contains full-length hashes so we don't return any prefix hit.
@@ -301,7 +297,6 @@ class SafeBrowsingDatabaseNew : public SafeBrowsingDatabase {
                                  base::Time last_update) OVERRIDE;
   virtual bool ContainsDownloadUrl(const std::vector<GURL>& urls,
                                    std::vector<SBPrefix>* prefix_hits) OVERRIDE;
-  virtual bool ContainsDownloadHashPrefix(const SBPrefix& prefix) OVERRIDE;
   virtual bool ContainsCsdWhitelistedUrl(const GURL& url) OVERRIDE;
   virtual bool ContainsDownloadWhitelistedUrl(const GURL& url) OVERRIDE;
   virtual bool ContainsDownloadWhitelistedString(