Tether: Break helper TimerFactory out of BleConnectionManager and HostScanCache.

chromeos/components/tether/host_scan_cache.h

Index: chromeos/components/tether/host_scan_cache.h
diff --git a/chromeos/components/tether/host_scan_cache.h b/chromeos/components/tether/host_scan_cache.h
index d3ab465f869cea1b7f0779ab50469a7ce4d237f4..3d705e48887befdade932759600fb22c07be863b 100644
--- a/chromeos/components/tether/host_scan_cache.h
+++ b/chromeos/components/tether/host_scan_cache.h
@@ -22,6 +22,7 @@ namespace tether {
 class ActiveHost;
 class DeviceIdTetherNetworkGuidMap;
 class TetherHostResponseRecorder;
+class TimerFactory;
 
 // Caches scan results and inserts them into the network stack.
 class HostScanCache : public TetherHostResponseRecorder::Observer {
@@ -76,11 +77,6 @@ class HostScanCache : public TetherHostResponseRecorder::Observer {
   // TetherHostResponseRecorder::Observer:
   void OnPreviouslyConnectedHostIdsChanged() override;
 
-  class TimerFactory {
-   public:
-    virtual std::unique_ptr<base::Timer> CreateOneShotTimer() = 0;
-  };
-
  private:
   friend class HostScanCacheTest;