Migrate AppWindowToken lists into DisplayContent.

In preparation for converting ActivityManager control to a task-based
interface the AppWindowTokens are being stored per-display.

Change-Id: Ie5e355219554523f5e56eaef138d382975cf1682
diff --git a/services/java/com/android/server/wm/TaskList.java b/services/java/com/android/server/wm/TaskList.java
new file mode 100644
index 0000000..fe12b98
--- /dev/null
+++ b/services/java/com/android/server/wm/TaskList.java
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2013 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.server.wm;
+
+import com.android.server.am.TaskGroup;
+
+class TaskList extends TaskGroup {
+//    private final String TAG = "TaskGroup";
+    AppTokenList mAppTokens = new AppTokenList();
+
+    TaskList(AppWindowToken wtoken) {
+        taskId = wtoken.groupId;
+        tokens.add(wtoken.appToken);
+        mAppTokens.add(wtoken);
+    }
+}