net: Add fuzzer for HostResolverImpl.

net/dns/dns_socket_pool.h

Index: net/dns/dns_socket_pool.h
diff --git a/net/dns/dns_socket_pool.h b/net/dns/dns_socket_pool.h
index 1e88a87691e878ce2402d40e316ce0f493bd5ddc..973a9508a80588506c39eea607be4611aedf8999 100644
--- a/net/dns/dns_socket_pool.h
+++ b/net/dns/dns_socket_pool.h
@@ -10,6 +10,7 @@
 
 #include "base/macros.h"
 #include "net/base/net_export.h"
+#include "net/base/rand_callback.h"
 #include "net/log/net_log.h"
 
 namespace net {
@@ -31,13 +32,15 @@ class NET_EXPORT_PRIVATE DnsSocketPool {
   // sockets.  (This varies by platform; see DnsSocketPoolImpl in
   // dns_socket_pool.cc for details.)
   static std::unique_ptr<DnsSocketPool> CreateDefault(
-      ClientSocketFactory* factory);
+      ClientSocketFactory* factory,
+      const RandIntCallback& rand_int_callback);
 
   // Creates a DnsSocketPool that implements a "null" strategy -- no sockets are
   // preallocated, allocation requests are satisfied by calling the factory
   // directly, and returned sockets are deleted immediately.
   static std::unique_ptr<DnsSocketPool> CreateNull(
-      ClientSocketFactory* factory);
+      ClientSocketFactory* factory,
+      const RandIntCallback& rand_int_callback);
 
   // Initializes the DnsSocketPool.  |nameservers| is the list of nameservers
   // for which the DnsSocketPool will manage sockets; |net_log| is the NetLog
@@ -67,7 +70,8 @@ class NET_EXPORT_PRIVATE DnsSocketPool {
                                                 const NetLog::Source& source);
 
  protected:
-  DnsSocketPool(ClientSocketFactory* socket_factory);
+  DnsSocketPool(ClientSocketFactory* socket_factory,
+                const RandIntCallback& rand_int_callback);
 
   void InitializeInternal(
       const std::vector<IPEndPoint>* nameservers,
@@ -76,8 +80,12 @@ class NET_EXPORT_PRIVATE DnsSocketPool {
   std::unique_ptr<DatagramClientSocket> CreateConnectedSocket(
       unsigned server_index);
 
+  // Returns a random int in the specified range.
+  int GetRandomInt(int min, int max);
+
  private:
   ClientSocketFactory* socket_factory_;
+  const RandIntCallback& rand_int_callback_;
   NetLog* net_log_;
   const std::vector<IPEndPoint>* nameservers_;
   bool initialized_;