Convert AppEngineConnection to use HttpTransport

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

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

java/google/registry/tools/HttpRequestFactoryComponent.java

@@ -0,0 +1,28 @@
+// 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.google.api.client.http.HttpRequestFactory;
+
+/**
+ * This is a Dagger component interface for providing request factories.
+ *
+ * <p>It is not annotated as a component because it's just an interface used as a dependency in
+ * other components.  We provide our own concrete implementations of this for creating specific
+ * connection types.
+ */
+interface HttpRequestFactoryComponent {
+  public HttpRequestFactory httpRequestFactory();
+}