[net/dns] Serve requests from HOSTS file if possible.

net/base/host_resolver_impl.h

Index: net/base/host_resolver_impl.h
diff --git a/net/base/host_resolver_impl.h b/net/base/host_resolver_impl.h
index dd8c70e334c285d75ff72691e1a5e0c51b9e10b4..16b304f4d706dd421550abe8f159cb8d0f1d451a 100644
--- a/net/base/host_resolver_impl.h
+++ b/net/base/host_resolver_impl.h
@@ -23,12 +23,11 @@
 #include "net/base/net_log.h"
 #include "net/base/network_change_notifier.h"
 #include "net/base/prioritized_dispatcher.h"
+#include "net/dns/dns_client.h"
 #include "net/dns/dns_config_service.h"
 
 namespace net {
 
-class DnsTransactionFactory;
-
 // For each hostname that is requested, HostResolver creates a
 // HostResolverImpl::Job. When this job gets dispatched it creates a ProcTask
 // which runs the given HostResolverProc on a WorkerPool thread. If requests for
@@ -153,6 +152,10 @@ class NET_EXPORT HostResolverImpl
     return dispatcher_.num_running_jobs();
   }
 
+  void set_dns_client_for_tests(scoped_ptr<DnsClient> client) {

[mmenke, 2012/03/13 15:56:27]

Suggest you make this and the above function private and friend the tests.

[szym, 2012/03/13 20:06:42]

Not a fan of FRIEND_TEST*. It completely opens the guts, makes the tests pollute
the namespace, and forces the test writer to edit the class header. I'd strongly
prefer if we could friend the fixture base class (HostResolverImplTest) and put
the rest of the tests in anonymous namespace.

For now, I moved the two tests out of the anonymous namespace. I hope to address
the namespace pollution when fixing http://crbug.com/117830

[mmenke, 2012/03/13 20:31:08]

SGTM.  I prefer just friending the fixture as well.

+    dns_client_ = client.Pass();
+  }
+
  private:
   class Job;
   class ProcTask;
@@ -184,10 +187,15 @@ class NET_EXPORT HostResolverImpl
   // if it is a positive entry.
   bool ServeFromCache(const Key& key,
                       const RequestInfo& info,
-                      const BoundNetLog& request_net_log,
                       int* net_error,
                       AddressList* addresses);
 
+  // If |key| is not found in the HOSTS file or no HOSTS file known, returns
+  // false, otherwise returns true and fills |addresses|.
+  bool ServeFromHosts(const Key& key,
+                      const RequestInfo& info,
+                      AddressList* addresses);
+
   // Notifies IPv6ProbeJob not to call back, and discard reference to the job.
   void DiscardIPv6ProbeJob();
 
@@ -212,6 +220,9 @@ class NET_EXPORT HostResolverImpl
   // Might start new jobs.
   void AbortAllInProgressJobs();
 
+  // Attempts to serve each Job in |jobs_| from the HOSTS file.
+  void TryServingAllJobsFromHosts();
+
   // NetworkChangeNotifier::IPAddressObserver:
   virtual void OnIPAddressChanged() OVERRIDE;
 
@@ -221,6 +232,9 @@ class NET_EXPORT HostResolverImpl
   // DnsConfigService::Observer:
   virtual void OnConfigChanged(const DnsConfig& dns_config) OVERRIDE;
 
+  // True if have fully configured DNS client.
+  bool HaveDnsConfig() const;
+
   // Cache of host resolution results.
   scoped_ptr<HostCache> cache_;
 
@@ -236,11 +250,10 @@ class NET_EXPORT HostResolverImpl
   // Parameters for ProcTask.
   ProcTaskParams proc_params_;
 
-  scoped_ptr<DnsTransactionFactory> dns_transaction_factory_;
-
   // Address family to use when the request doesn't specify one.
   AddressFamily default_address_family_;
 
+  scoped_ptr<DnsClient> dns_client_;
   scoped_ptr<DnsConfigService> dns_config_service_;
 
   // Indicate if probing is done after each network change event to set address