Upstream most of ios/web/net

ios/net/request_tracker.h

Index: ios/net/request_tracker.h
diff --git a/ios/net/request_tracker.h b/ios/net/request_tracker.h
index e47b732a2b1ddbfc570747167a9c36f0d5112610..f21cb887c7c12686258cbbefb145a5311104d6d7 100644
--- a/ios/net/request_tracker.h
+++ b/ios/net/request_tracker.h
@@ -44,6 +44,8 @@ class RequestTracker {
 
   class RequestTrackerFactory {
    public:
+    virtual ~RequestTrackerFactory();
+
     // Returns false if |request| is associated to an invalid tracker and should
     // be cancelled. In this case |tracker| is set to nullptr.
     // Returns true if |request| is associated with a valid tracker or if the