Add initialization step to set lfs.plugin value in gerrit.config

Change-Id: Ic540db290e61759ddebd8b40077295e5e41d1351
diff --git a/BUCK b/BUCK
index 409fd6d..b0f1d05 100644
--- a/BUCK
+++ b/BUCK
@@ -21,6 +21,7 @@
     'Gerrit-Module: com.googlesource.gerrit.plugins.lfs.Module',
     'Gerrit-HttpModule: com.googlesource.gerrit.plugins.lfs.HttpModule',
     'Gerrit-SshModule: com.googlesource.gerrit.plugins.lfs.SshModule',
+    'Gerrit-InitStep: com.googlesource.gerrit.plugins.lfs.InitLfs',
   ],
 )
 
@@ -74,4 +75,4 @@
     ':lfs__plugin',
     '//plugins/lfs:jgit-lfs',
   ],
-)
\ No newline at end of file
+)
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/InitLfs.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/InitLfs.java
new file mode 100644
index 0000000..b6cddfa
--- /dev/null
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/InitLfs.java
@@ -0,0 +1,43 @@
+// Copyright (C) 2017 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.lfs;
+
+import com.google.gerrit.extensions.annotations.PluginName;
+import com.google.gerrit.pgm.init.api.InitStep;
+import com.google.gerrit.pgm.init.api.Section;
+import com.google.inject.Inject;
+
+public class InitLfs implements InitStep {
+  private static final String LFS_SECTION = "lfs";
+  private static final String PLUGIN_KEY = "plugin";
+
+  private final String name;
+  private final Section lfs;
+
+  @Inject
+  InitLfs(@PluginName String name, Section.Factory sections) {
+    this.name = name;
+    this.lfs = sections.get(LFS_SECTION, null);
+  }
+
+  @Override
+  public void run() throws Exception {
+    lfs.set(PLUGIN_KEY, name);
+  }
+
+  @Override
+  public void postRun() throws Exception {
+  }
+}