Pass pref_task_runner through HttpServerPropertiesManager's cxtor so that tests could inject a Test…

net/http/http_server_properties_manager.h

 // Copyright 2014 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_HTTP_HTTP_SERVER_PROPERTIES_MANAGER_H_
 #define NET_HTTP_HTTP_SERVER_PROPERTIES_MANAGER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 22 matching lines @@
 ////////////////////////////////////////////////////////////////////////////////
 // HttpServerPropertiesManager
 
 // The manager for creating and updating an HttpServerProperties (for example it
 // tracks if a server supports SPDY or not).
 //
 // This class interacts with both the pref thread, where notifications of pref
 // changes are received from, and the network thread, which owns it, and it
 // persists the changes from network stack whether server supports SPDY or not.
 //
-// It must be constructed on the pref thread, to set up |pref_task_runner_| and
-// the prefs listeners.
+// There are two SingleThreadTaskRunners:
+// |pref_task_runner_| should be bound with the pref thread and is used to post
+// cache update to the pref thread;
+// |network_task_runner_| should be bound with the network thread and is used
+// to post pref update to the cache thread.
+//
+// It must be constructed with correct task runners passed in to set up
+// |pref_task_runner_| and |network_task_runner| as well as the prefs listeners.
 //
 // ShutdownOnPrefThread must be called from pref thread before destruction, to
 // release the prefs listeners on the pref thread.
 //
 // Class requires that update tasks from the Pref thread can post safely to the
 // network thread, so the destruction order must guarantee that if |this|
 // exists in pref thread, then a potential destruction on network thread will
 // come after any task posted to network thread from that method on pref thread.
 // This is used to go through network thread before the actual update starts,
 // and grab a WeakPtr.
@@ skipping 19 matching lines @@
     virtual void StartListeningForUpdates(const base::Closure& callback) = 0;
     virtual void StopListeningForUpdates() = 0;
   };
 
   // Create an instance of the HttpServerPropertiesManager.
   //
   // Ownership of the PrefDelegate pointer is taken by this class. This is
   // passed as a raw pointer rather than a scoped_refptr currently because
   // the test uses gmock and it doesn't forward move semantics properly.
   //
-  // Must be constructed on the Pref thread.
+  // There are two SingleThreadTaskRunners:
+  // |pref_task_runner| should be bound with the pref thread and is used to post
+  // cache update to the pref thread;
+  // |network_task_runner| should be bound with the network thread and is used
+  // to post pref update to the cache thread.
   HttpServerPropertiesManager(
       PrefDelegate* pref_delegate,
+      scoped_refptr<base::SingleThreadTaskRunner> pref_task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> network_task_runner);
   ~HttpServerPropertiesManager() override;
 
   // Initialize on Network thread.
   void InitializeOnNetworkThread();
 
   // Prepare for shutdown. Must be called on the Pref thread before destruction.
   void ShutdownOnPrefThread();
 
   // Helper function for unit tests to set the version in the dictionary.
@@ skipping 208 matching lines @@
   // Used to get |weak_ptr_| to self on the network thread.
   std::unique_ptr<base::WeakPtrFactory<HttpServerPropertiesManager>>
       network_weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(HttpServerPropertiesManager);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_SERVER_PROPERTIES_MANAGER_H_