Do not duplicate FD in SmbProviderClient

This change fixes an issue where FileDescriptors were being duplicated,
and as a result leaked, when writing them into a proto to send over
D-Bus

Bug: chromium:881615
Change-Id: I6e7e7abce34a537c3d9228cf9baa6d1d9074625f
Reviewed-on: https://chromium-review.googlesource.com/1211877Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Commit-Queue: Zentaro Kavanagh <zentaro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589378}

chromeos/dbus/smb_provider_client.cc

@@ -76,7 +76,7 @@ class SmbProviderClientImpl : public SmbProviderClient {
                                  smbprovider::kMountMethod);
     dbus::MessageWriter writer(&method_call);
     writer.AppendProtoAsArrayOfBytes(options);
-    writer.AppendFileDescriptor(password_fd.release());
+    writer.AppendFileDescriptor(password_fd.get());
     CallMethod(&method_call, &SmbProviderClientImpl::HandleMountCallback,
                &callback);
   }
@@ -97,7 +97,7 @@ class SmbProviderClientImpl : public SmbProviderClient {
                                  smbprovider::kRemountMethod);
     dbus::MessageWriter writer(&method_call);
     writer.AppendProtoAsArrayOfBytes(options);
-    writer.AppendFileDescriptor(password_fd.release());
+    writer.AppendFileDescriptor(password_fd.get());
 
     CallDefaultMethod(&method_call, &callback);
   }
@@ -214,7 +214,7 @@ class SmbProviderClientImpl : public SmbProviderClient {
                                  smbprovider::kWriteFileMethod);
     dbus::MessageWriter writer(&method_call);
     writer.AppendProtoAsArrayOfBytes(options);
-    writer.AppendFileDescriptor(temp_fd.release());
+    writer.AppendFileDescriptor(temp_fd.get());
     CallDefaultMethod(&method_call, &callback);
   }