Introduce DisplayArea organizer

Similar to task organizer this allows for the organization of display
areas.

Test: they pass!
Bug: 147406652
Bug: 152113464
Bug: 152117221
Change-Id: Id0dbec20f0aedc5162f4ff7be81b2dafb0c8f3c9
diff --git a/core/java/android/window/IDisplayAreaOrganizer.aidl b/core/java/android/window/IDisplayAreaOrganizer.aidl
new file mode 100644
index 0000000..1045ab2
--- /dev/null
+++ b/core/java/android/window/IDisplayAreaOrganizer.aidl
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2020 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 android.window;
+
+import android.window.IWindowContainer;
+
+/**
+ * Interface for WindowManager to delegate control of display areas.
+ * {@hide}
+ */
+oneway interface IDisplayAreaOrganizer {
+    void onDisplayAreaAppeared(in IWindowContainer displayArea);
+    void onDisplayAreaVanished(in IWindowContainer displayArea);
+}