Introduce ERR_NETWORK_CHANGED and allow URLFetcher to automatically retry on that error.

net/base/mock_host_resolver.h

 // Copyright (c) 2011 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.
 
 #ifndef NET_BASE_MOCK_HOST_RESOLVER_H_
 #define NET_BASE_MOCK_HOST_RESOLVER_H_
 
 #include <list>
 #include <map>
 
@@ skipping 47 matching lines @@
   virtual ~MockHostResolverBase();
 
   RuleBasedHostResolverProc* rules() { return rules_; }
   void set_rules(RuleBasedHostResolverProc* rules) { rules_ = rules; }
 
   // Controls whether resolutions complete synchronously or asynchronously.
   void set_synchronous_mode(bool is_synchronous) {
     synchronous_mode_ = is_synchronous;
   }
 
+  // Asynchronous requests are automatically resolved by default.
+  // If set_ondemand_mode() is set then Resolve() returns IO_PENDING and
+  // ResolveAllPending() must be explicitly invoked to resolve all requests
+  // that are pending.
+  void set_ondemand_mode(bool is_ondemand) {
+    ondemand_mode_ = is_ondemand;
+  }
+
   // HostResolver methods:
   virtual int Resolve(const RequestInfo& info,
                       AddressList* addresses,
                       const CompletionCallback& callback,
                       RequestHandle* out_req,
                       const BoundNetLog& net_log) OVERRIDE;
   virtual int ResolveFromCache(const RequestInfo& info,
                                AddressList* addresses,
                                const BoundNetLog& net_log) OVERRIDE;
   virtual void CancelRequest(RequestHandle req) OVERRIDE;
   virtual HostCache* GetHostCache() OVERRIDE;
 
+  // Resolves all pending requests. It is only valid to invoke this if
+  // set_ondemand_mode was set before. The requests are resolved asynchronously,
+  // after this call returns.
+  void ResolveAllPending();
+
+  // Returns true if there are pending requests that can be resolved by invoking
+  // ResolveAllPending().
+  bool has_pending_requests() const { return !requests_.empty(); }
+
  protected:
   explicit MockHostResolverBase(bool use_caching);
 
  private:
   struct Request;
   typedef std::map<size_t, Request*> RequestMap;
 
   // Resolve as IP or from |cache_| return cached error or
   // DNS_CACHE_MISS if failed.
   int ResolveFromIPLiteralOrCache(const RequestInfo& info,
                                   AddressList* addresses);
   // Resolve via |proc_|.
   int ResolveProc(size_t id, const RequestInfo& info, AddressList* addresses);
   // Resolve request stored in |requests_|. Pass rv to callback.
   void ResolveNow(size_t id);
 
   bool synchronous_mode_;
+  bool ondemand_mode_;
   scoped_refptr<RuleBasedHostResolverProc> rules_;
   scoped_ptr<HostCache> cache_;
   RequestMap requests_;
   size_t next_request_id_;
 
   DISALLOW_COPY_AND_ASSIGN(MockHostResolverBase);
 };
 
 class MockHostResolver : public MockHostResolverBase {
  public:
@@ skipping 102 matching lines @@
   void Init(HostResolverProc* proc);
 
  private:
   scoped_refptr<HostResolverProc> current_proc_;
   scoped_refptr<HostResolverProc> previous_proc_;
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_MOCK_HOST_RESOLVER_H_