SafeBrowsing: Track and cancel API checks.

components/safe_browsing_db/database_manager.h

Index: components/safe_browsing_db/database_manager.h
diff --git a/components/safe_browsing_db/database_manager.h b/components/safe_browsing_db/database_manager.h
index c2359f67b4b8c865d1a40f0af8930c3022ebfd4b..e21297a1b5d8b0dbe067a3870f16cecf33025a45 100644
--- a/components/safe_browsing_db/database_manager.h
+++ b/components/safe_browsing_db/database_manager.h
@@ -174,10 +174,14 @@ class SafeBrowsingDatabaseManager
   // are handled separately. To cancel an API check use CancelApiCheck.
   virtual void CancelCheck(Client* client) = 0;
 
-  // TODO(kcarattini): Add a CancelApiCheck method.
+  // Called on the IO thread to cancel a pending API check if the result is no
+  // longer needed. Returns true if the client was found and the check
+  // successfully cancelled.
+  virtual bool CancelApiCheck(Client* client);
 
   // Called on the IO thread to check if the given url has blacklisted APIs.
-  // "client" is called asynchronously with the result when it is ready.
+  // "client" is called asynchronously with the result when it is ready. Clients
+  // should wait for results before calling this method a second time.

[Nathan Parker, 2016/04/15 23:27:35]

We probably want a dcheck to enforce that.

[kcarattini, 2016/04/18 03:00:09]

Done.

   // This method has the same implementation for both the local and remote
   // database managers since it pings Safe Browsing servers directly without
   // accessing the database at all.  Returns true if we can synchronously
@@ -218,6 +222,13 @@ class SafeBrowsingDatabaseManager
                            HandleGetHashesWithApisResultsNoMatch);
   FRIEND_TEST_ALL_PREFIXES(SafeBrowsingDatabaseManagerTest,
                            HandleGetHashesWithApisResultsMatches);
+  FRIEND_TEST_ALL_PREFIXES(SafeBrowsingDatabaseManagerTest,
+                           CancelApiCheck);
+
+  typedef std::set<std::shared_ptr<SafeBrowsingApiCheck> > CurrentApiChecks;
+
+  // In-progress checks.
+  CurrentApiChecks api_checks_;
 
   // Created and destroyed via StartOnIOThread/StopOnIOThread.
   V4GetHashProtocolManager* v4_get_hash_protocol_manager_;