Handle timeout for update requests.

components/safe_browsing_db/v4_update_protocol_manager.h

Index: components/safe_browsing_db/v4_update_protocol_manager.h
diff --git a/components/safe_browsing_db/v4_update_protocol_manager.h b/components/safe_browsing_db/v4_update_protocol_manager.h
index 7da1667c66f5012bd8949e5bfe8d1bc25e88323e..14ae93ead1fd0cb2264bd8e9745412edb0f29a30 100644
--- a/components/safe_browsing_db/v4_update_protocol_manager.h
+++ b/components/safe_browsing_db/v4_update_protocol_manager.h
@@ -87,6 +87,8 @@ class V4UpdateProtocolManager : public net::URLFetcherDelegate,
                            TestGetUpdatesWithOneBackoff);
   FRIEND_TEST_ALL_PREFIXES(V4UpdateProtocolManagerTest,
                            TestBase64EncodingUsesUrlEncoding);
+  FRIEND_TEST_ALL_PREFIXES(V4UpdateProtocolManagerTest,
+                           TestGetUpdatesHasTimeout);
   friend class V4UpdateProtocolManagerFactoryImpl;
 
   // Fills a FetchThreatListUpdatesRequest protocol buffer for a request.
@@ -111,6 +113,10 @@ class V4UpdateProtocolManager : public net::URLFetcherDelegate,
   // Resets the update error counter and multiplier.
   void ResetUpdateErrors();
 
+  // Called when update request times out. Cancels the existing request and
+  // re-sends the update request.
+  void HandleTimeout();
+
   // Updates internal update and backoff state for each update response error,
   // assuming that the current time is |now|.
   void HandleUpdateError(const base::Time& now);
@@ -172,6 +178,9 @@ class V4UpdateProtocolManager : public net::URLFetcherDelegate,
 
   base::Time last_response_time_;
 
+  // Used to interrupt and re-issue update requests that take too long.
+  base::OneShotTimer timeout_timer_;
+
   DISALLOW_COPY_AND_ASSIGN(V4UpdateProtocolManager);
 };