[chromedriver] Reuse forwarded adb ports.

chrome/test/chromedriver/net/port_server.h

Index: chrome/test/chromedriver/net/port_server.h
diff --git a/chrome/test/chromedriver/net/port_server.h b/chrome/test/chromedriver/net/port_server.h
index 3d32950373f5b1081826c4895857e0062f96a64e..89af0c36b2175aa0da7183622595235b68ed74ec 100644
--- a/chrome/test/chromedriver/net/port_server.h
+++ b/chrome/test/chromedriver/net/port_server.h
@@ -54,13 +54,19 @@ class PortManager {
   ~PortManager();
 
   Status ReservePort(int* port, scoped_ptr<PortReservation>* reservation);
+  // Since we cannot remove forwarded adb ports on older SDKs,
+  // maintain a pool of forwarded ports for reuse.
+  Status ReservePortFromPool(int* port,
+                             scoped_ptr<PortReservation>* reservation);
 
  private:
+  int FindAvailablePort() const;
   void ReleasePort(int port);
+  void ReleasePortToPool(int port);
 
-  base::Lock taken_lock_;
+  base::Lock lock_;
   std::set<int> taken_;
-
+  std::list<int> unused_forwarded_port_;
   int min_port_;
   int max_port_;
 };