Set up no-op package (#425)

Summary:
Pull Request resolved: https://github.com/facebook/flipper/pull/425

Incomplete implementation that should allow for most uses
as a release-only package.

Next steps:
- Integrate sample app with this.
- Set up CI to build sample app in release mode with this.
- Register with JCenter.
- Automatically publish to JCenter as part of our release step.

Reviewed By: jknoxville

Differential Revision: D15146823

fbshipit-source-id: 3ad058dce7b0395721c6e6715d44d4d51b1834da

android/no-op/src/main/AndroidManifest.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.facebook.flipper">
+</manifest>

android/no-op/src/main/java/com/facebook/flipper/android/AndroidFlipperClient.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the LICENSE
+ * file in the root directory of this source tree.
+ */
+package com.facebook.flipper.android;
+
+import android.content.Context;
+import com.facebook.flipper.core.FlipperClient;
+
+public final class AndroidFlipperClient {
+  public static FlipperClient getInstance(Context context) {
+    return new NoOpAndroidFlipperClient();
+  }
+
+  public static FlipperClient getInstanceIfInitialized() {
+    return new NoOpAndroidFlipperClient();
+  }
+}

android/no-op/src/main/java/com/facebook/flipper/android/NoOpAndroidFlipperClient.java

@@ -0,0 +1,52 @@
+/*
+ *  Copyright (c) Facebook, Inc.
+ *
+ *  This source code is licensed under the MIT license found in the LICENSE
+ *  file in the root directory of this source tree.
+ *
+ */
+package com.facebook.flipper.android;
+
+import com.facebook.flipper.core.FlipperClient;
+import com.facebook.flipper.core.FlipperPlugin;
+import javax.annotation.Nullable;
+
+public class NoOpAndroidFlipperClient implements FlipperClient {
+
+  @Override
+  public void addPlugin(FlipperPlugin plugin) {
+    // no-op
+  }
+
+  @Nullable
+  @Override
+  public <T extends FlipperPlugin> T getPlugin(String id) {
+    return null;
+  }
+
+  @Nullable
+  @Override
+  public <T extends FlipperPlugin> T getPluginByClass(Class<T> cls) {
+    return null;
+  }
+
+  @Override
+  public void removePlugin(FlipperPlugin plugin) {
+    // no-op
+  }
+
+  @Override
+  public void start() {
+    // no-op
+  }
+
+  @Override
+  public void stop() {
+    // no-op
+  }
+
+  @Override
+  public void unsubscribe() {
+    // no-op
+  }
+}

android/no-op/src/main/java/com/facebook/flipper/core/FlipperClient.java

@@ -0,0 +1,28 @@
+/*
+ *  Copyright (c) Facebook, Inc.
+ *
+ *  This source code is licensed under the MIT license found in the LICENSE
+ *  file in the root directory of this source tree.
+ *
+ */
+package com.facebook.flipper.core;
+
+import javax.annotation.Nullable;
+
+public interface FlipperClient {
+  void addPlugin(FlipperPlugin plugin);
+
+  @Nullable
+  <T extends FlipperPlugin> T getPlugin(String id);
+
+  @Nullable
+  <T extends FlipperPlugin> T getPluginByClass(Class<T> cls);
+
+  void removePlugin(FlipperPlugin plugin);
+
+  void start();
+
+  void stop();
+
+  void unsubscribe();
+}

android/no-op/src/main/java/com/facebook/flipper/core/FlipperPlugin.java

@@ -0,0 +1,10 @@
+/*
+ *  Copyright (c) 2018-present, Facebook, Inc.
+ *
+ *  This source code is licensed under the MIT license found in the LICENSE
+ *  file in the root directory of this source tree.
+ *
+ */
+package com.facebook.flipper.core;
+
+public interface FlipperPlugin {}