shill: Clear explicitly_disconnected_ on resume

This lets us retry networks that may have been flaky in the past on
resume, when the environment may have changed.

BUG=chromium-os:25213
TEST=Unit test

Change-Id: I308f8d35d1446efebdd5abd65da899c8a483ac36
Reviewed-on: https://gerrit.chromium.org/gerrit/34363
Commit-Ready: Christopher Wiley <wiley@chromium.org>
Reviewed-by: Christopher Wiley <wiley@chromium.org>
Tested-by: Christopher Wiley <wiley@chromium.org>
diff --git a/service_unittest.cc b/service_unittest.cc
index d3d143e..00349f1 100644
--- a/service_unittest.cc
+++ b/service_unittest.cc
@@ -465,8 +465,11 @@
   service_->Disconnect(&error);
   EXPECT_TRUE(service_->IsAutoConnectable(&reason));
 
-  // TODO(quiche): After we have resume handling in place, test that
-  // we re-enable auto-connect on resume. crosbug.com/25213
+  // A resume also re-enables auto-connect.
+  service_->UserInitiatedDisconnect(&error);
+  EXPECT_FALSE(service_->IsAutoConnectable(&reason));
+  service_->OnAfterResume();
+  EXPECT_TRUE(service_->IsAutoConnectable(&reason));
 
   service_->SetState(Service::kStateConnected);
   EXPECT_FALSE(service_->IsAutoConnectable(&reason));