Convert AppEngineConnection to use HttpTransport

Make AppEngineConnection use HttpTransport through HttpRequestFactory and
create factory factories for localhost and HTTPOverRPC.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=143680257

java/google/registry/tools/AppEngineConnectionFlags.java

@@ -0,0 +1,38 @@
+// Copyright 2016 The Nomulus Authors. All Rights Reserved.
+//
+// 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 google.registry.tools;
+
+import com.beust.jcommander.Parameter;
+import com.beust.jcommander.Parameters;
+import com.google.common.net.HostAndPort;
+import google.registry.config.RegistryEnvironment;
+
+/**
+ * Class to contain the configuration flags for AppEngineConnection.
+ *
+ * <p>This is broken out into its own class to make it cleaner to extract these from the dagger
+ * module, where these values are injected.
+ */
+@Parameters(separators = " =")
+class AppEngineConnectionFlags {
+
+  @Parameter(names = "--server", description = "HOST[:PORT] to which remote commands are sent.")
+  private static HostAndPort server = RegistryEnvironment.get().config().getServer();
+
+  HostAndPort getServer() {
+    return server;
+  }
+}
+