Adds SB V4 response handler to Protocol Manager.

components/safe_browsing_db/util.h

 // Copyright (c) 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Utilities for the SafeBrowsing DB code.
 
 #ifndef COMPONENTS_SAFE_BROWSING_DB_UTIL_H_
 #define COMPONENTS_SAFE_BROWSING_DB_UTIL_H_
 
 #include <stdint.h>
@@ skipping 47 matching lines @@
   char full_hash[32];
   SBPrefix prefix;
 };
 
 // Used when we get a gethash response.
 struct SBFullHashResult {
   SBFullHash hash;
   // TODO(shess): Refactor to allow ListType here.
   int list_id;
   std::string metadata;
+  // Used only for V4 results. The cache lifetime for this result. The response
+  // must not be cached for more than this duration to avoid false positives.
+  base::TimeDelta cache_duration;

[Nathan Parker, 2016/01/11 23:50:32]

How does this relate to the SBCachedFullHashResult::expire_after? Is
expire_after not used for v4 responses?

[kcarattini, 2016/01/12 00:43:34]

SBCachedFullHashResult is used by the database, and it looks like it takes the
cache_lifetime passed to the callback and sets that value for all hashes in the
cache that were part of the same request. In V4, there can be a different
cache_duration per hash (as opposed to per request), so we need a way to capture
that in the results that are passed to the callback. If we end up using the
SBCachedFullHashResult in the database manager (and I suspect we will), then
yes, this cache_duration will be used to the the expire_after field.

 };
 
 // Caches individual response from GETHASH request.
 struct SBCachedFullHashResult {
   SBCachedFullHashResult();
   explicit SBCachedFullHashResult(const base::Time& in_expire_after);
   ~SBCachedFullHashResult();
 
   base::Time expire_after;
   std::vector<SBFullHashResult> full_hashes;
@@ skipping 87 matching lines @@
 
 // Given a URL, returns all the paths we need to check.
 void GeneratePathsToCheck(const GURL& url, std::vector<std::string>* paths);
 
 // Given a URL, returns all the patterns we need to check.
 void GeneratePatternsToCheck(const GURL& url, std::vector<std::string>* urls);
 
 }  // namespace safe_browsing
 
 #endif  // COMPONENTS_SAFE_BROWSING_DB_UTIL_H_