Removing number of threads used in background execution
to prevent system thrashing

Bug: 188541475
Test: Presubmit
Change-Id: Iff73abeab813d1b80a1ff85b69723dce0bef8005
diff --git a/quickstep/src/com/android/quickstep/RecentsAnimationController.java b/quickstep/src/com/android/quickstep/RecentsAnimationController.java
index f2bd916..462f714 100644
--- a/quickstep/src/com/android/quickstep/RecentsAnimationController.java
+++ b/quickstep/src/com/android/quickstep/RecentsAnimationController.java
@@ -16,7 +16,6 @@
 package com.android.quickstep;
 
 import static com.android.launcher3.util.Executors.MAIN_EXECUTOR;
-import static com.android.launcher3.util.Executors.THREAD_POOL_EXECUTOR;
 import static com.android.launcher3.util.Executors.UI_HELPER_EXECUTOR;
 
 import android.view.SurfaceControl;
@@ -102,7 +101,7 @@
      */
     @UiThread
     public void removeTaskTarget(@NonNull RemoteAnimationTargetCompat target) {
-        THREAD_POOL_EXECUTOR.execute(() -> mController.removeTask(target.taskId));
+        UI_HELPER_EXECUTOR.execute(() -> mController.removeTask(target.taskId));
     }
 
     @UiThread
diff --git a/robolectric_tests/src/com/android/launcher3/model/ModelMultiCallbacksTest.java b/robolectric_tests/src/com/android/launcher3/model/ModelMultiCallbacksTest.java
index aab6c25..a2abfd5 100644
--- a/robolectric_tests/src/com/android/launcher3/model/ModelMultiCallbacksTest.java
+++ b/robolectric_tests/src/com/android/launcher3/model/ModelMultiCallbacksTest.java
@@ -15,7 +15,7 @@
  */
 package com.android.launcher3.model;
 
-import static com.android.launcher3.util.Executors.createAndStartNewForegroundLooper;
+import static com.android.launcher3.util.Executors.createAndStartNewLooper;
 import static com.android.launcher3.util.LauncherModelHelper.TEST_PACKAGE;
 
 import static org.junit.Assert.assertEquals;
@@ -74,7 +74,7 @@
 
         // Since robolectric tests run on main thread, we run the loader-UI calls on a temp thread,
         // so that we can wait appropriately for the loader to complete.
-        mTempMainExecutor = new LooperExecutor(createAndStartNewForegroundLooper("tempMain"));
+        mTempMainExecutor = new LooperExecutor(createAndStartNewLooper("tempMain"));
         ShadowLooperExecutor sle = Shadow.extract(Executors.MAIN_EXECUTOR);
         sle.setHandler(mTempMainExecutor.getHandler());
     }
diff --git a/src/com/android/launcher3/util/Executors.java b/src/com/android/launcher3/util/Executors.java
index a85ae45..6329540 100644
--- a/src/com/android/launcher3/util/Executors.java
+++ b/src/com/android/launcher3/util/Executors.java
@@ -30,18 +30,15 @@
  */
 public class Executors {
 
-    // These values are same as that in {@link AsyncTask}.
-    private static final int CPU_COUNT = Runtime.getRuntime().availableProcessors();
-    private static final int CORE_POOL_SIZE = CPU_COUNT + 1;
-    private static final int MAXIMUM_POOL_SIZE = CPU_COUNT * 2 + 1;
+    private static final int POOL_SIZE =
+            Math.max(Runtime.getRuntime().availableProcessors(), 2);
     private static final int KEEP_ALIVE = 1;
 
     /**
      * An {@link ThreadPoolExecutor} to be used with async task with no limit on the queue size.
      */
     public static final ThreadPoolExecutor THREAD_POOL_EXECUTOR = new ThreadPoolExecutor(
-            CORE_POOL_SIZE, MAXIMUM_POOL_SIZE, KEEP_ALIVE,
-            TimeUnit.SECONDS, new LinkedBlockingQueue<>());
+            POOL_SIZE, POOL_SIZE, KEEP_ALIVE, TimeUnit.SECONDS, new LinkedBlockingQueue<>());
 
     /**
      * Returns the executor for running tasks on the main thread.
@@ -53,7 +50,8 @@
      * A background executor for using time sensitive actions where user is waiting for response.
      */
     public static final LooperExecutor UI_HELPER_EXECUTOR =
-            new LooperExecutor(createAndStartNewForegroundLooper("UiThreadHelper"));
+            new LooperExecutor(
+                    createAndStartNewLooper("UiThreadHelper", Process.THREAD_PRIORITY_FOREGROUND));
 
     /**
      * Utility method to get a started handler thread statically
@@ -72,15 +70,6 @@
     }
 
     /**
-     * Similar to {@link #createAndStartNewLooper(String)}, but starts the thread with
-     * foreground priority.
-     * Think before using
-     */
-    public static Looper createAndStartNewForegroundLooper(String name) {
-        return createAndStartNewLooper(name, Process.THREAD_PRIORITY_FOREGROUND);
-    }
-
-    /**
      * Executor used for running Launcher model related tasks (eg loading icons or updated db)
      */
     public static final LooperExecutor MODEL_EXECUTOR =