Adding support for overlay and corresponding plugin to Launcher

Updating various task callbacks to handle overlays

Change-Id: I80077508ad35c31269c873f51f0105302a9e6a5d

src_plugins/com/android/systemui/plugins/OverlayPlugin.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2019 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.android.systemui.plugins;
+
+import android.app.Activity;
+
+import com.android.systemui.plugins.annotations.ProvidesInterface;
+import com.android.systemui.plugins.shared.LauncherExterns;
+import com.android.systemui.plugins.shared.LauncherOverlayManager;
+
+/**
+ * Implement this interface to add a -1 content on the home screen.
+ */
+@ProvidesInterface(action = OverlayPlugin.ACTION, version = OverlayPlugin.VERSION)
+public interface OverlayPlugin extends Plugin {
+    String ACTION = "com.android.systemui.action.PLUGIN_LAUNCHER_OVERLAY";
+    int VERSION = 1;
+
+    LauncherOverlayManager createOverlayManager(Activity activity, LauncherExterns externs);
+
+}