Add DevicePortForwarder with adb fix

packages/flutter_tools/lib/src/device.dart

diff --git a/packages/flutter_tools/lib/src/device.dart b/packages/flutter_tools/lib/src/device.dart
index f8cdda3..b948515 100644
--- a/packages/flutter_tools/lib/src/device.dart
+++ b/packages/flutter_tools/lib/src/device.dart
@@ -151,6 +151,9 @@
   /// Get the log reader for this device.
   DeviceLogReader get logReader;
 
+  /// Get the port forwarder for this device.
+  DevicePortForwarder get portForwarder;
+
   /// Clear the device's logs.
   void clearLogs();
 
@@ -186,6 +189,30 @@
   String toString() => '$runtimeType $id';
 }
 
+class ForwardedPort {
+  ForwardedPort(this.hostPort, this.devicePort);
+
+  final int hostPort;
+  final int devicePort;
+
+  String toString() => 'ForwardedPort HOST:$hostPort to DEVICE:$devicePort';
+}
+
+/// Forward ports from the host machine to the device.
+abstract class DevicePortForwarder {
+  /// Returns a Future that completes with the current list of forwarded
+  /// ports for this device.
+  List<ForwardedPort> get forwardedPorts;
+
+  /// Forward [hostPort] on the host to [devicePort] on the device.
+  /// If [hostPort] is null, will auto select a host port.
+  /// Returns a Future that completes with the host port.
+  Future<int> forward(int devicePort, {int hostPort: null});
+
+  /// Stops forwarding [forwardedPort].
+  Future unforward(ForwardedPort forwardedPort);
+}
+
 /// Read the log for a particular device. Subclasses must implement `hashCode`
 /// and `operator ==` so that log readers that read from the same location can be
 /// de-duped. For example, two Android devices will both try and log using