Overscroll plugin - give the plugin its own factory.

Separate out the overscroll plugin from the task overlay.
These two classes aren't really related.

Bug: 162012217
Tested: checked plugin still works
Change-Id: Id89eff1ad2ae9766efaaecd8cfc66d6521b9ca8c

quickstep/recents_ui_overrides/src/com/android/quickstep/OverscrollPluginFactory.java

@@ -0,0 +1,40 @@
+/*
+ * 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 com.android.quickstep;
+
+import static com.android.launcher3.util.MainThreadInitializedObject.forOverride;
+
+import com.android.launcher3.R;
+import com.android.launcher3.util.MainThreadInitializedObject;
+import com.android.launcher3.util.ResourceBasedOverride;
+import com.android.systemui.plugins.OverscrollPlugin;
+
+/**
+ * Resource overrideable factory for forcing a local overscroll plugin.
+ * Override {@link R.string#overscroll_plugin_factory_class} to set a different class.
+ */
+public class OverscrollPluginFactory implements ResourceBasedOverride {
+    public static final MainThreadInitializedObject<OverscrollPluginFactory> INSTANCE = forOverride(
+            OverscrollPluginFactory.class,
+            R.string.overscroll_plugin_factory_class);
+
+    /**
+     * Get the plugin that is defined locally in launcher, as opposed to a dynamic side loaded one.
+     */
+    public OverscrollPlugin getLocalOverscrollPlugin() {
+        return null;
+    }
+}

quickstep/recents_ui_overrides/src/com/android/quickstep/TaskOverlayFactory.java

@@ -45,7 +45,6 @@ import com.android.quickstep.util.RecentsOrientedState;
 import com.android.quickstep.views.OverviewActionsView;
 import com.android.quickstep.views.TaskThumbnailView;
 import com.android.quickstep.views.TaskView;
-import com.android.systemui.plugins.OverscrollPlugin;
 import com.android.systemui.shared.recents.model.Task;
 import com.android.systemui.shared.recents.model.ThumbnailData;
 
@@ -94,13 +93,6 @@ public class TaskOverlayFactory implements ResourceBasedOverride {
     public static final MainThreadInitializedObject<TaskOverlayFactory> INSTANCE =
             forOverride(TaskOverlayFactory.class, R.string.task_overlay_factory_class);
 
-    /**
-     * @return a launcher-provided OverscrollPlugin if available, otherwise null
-     */
-    public OverscrollPlugin getLocalOverscrollPlugin() {
-        return null;
-    }
-
     public TaskOverlay createOverlay(TaskThumbnailView thumbnailView) {
         return new TaskOverlay(thumbnailView);
     }

quickstep/recents_ui_overrides/src/com/android/quickstep/TouchInteractionService.java

@@ -597,9 +597,8 @@ public class TouchInteractionService extends Service implements PluginListener<O
             if (FeatureFlags.ENABLE_QUICK_CAPTURE_GESTURE.get()) {
                 OverscrollPlugin plugin = null;
                 if (FeatureFlags.FORCE_LOCAL_OVERSCROLL_PLUGIN.get()) {
-                    TaskOverlayFactory factory =
-                            TaskOverlayFactory.INSTANCE.get(getApplicationContext());
-                    plugin = factory.getLocalOverscrollPlugin();  // may be null
+                    plugin = OverscrollPluginFactory.INSTANCE.get(
+                            getApplicationContext()).getLocalOverscrollPlugin();
                 }
 
                 // If not local plugin was forced, use the actual overscroll plugin if available.

quickstep/res/values/config.xml

@@ -16,6 +16,8 @@
 <resources>
     <string name="task_overlay_factory_class" translatable="false"/>
 
+    <string name="overscroll_plugin_factory_class" translatable="false" />
+
     <!-- Activities which block home gesture -->
     <string-array name="gesture_blocking_activities" translatable="false">
         <item>com.android.launcher3/com.android.quickstep.interaction.GestureSandboxActivity</item>