Adding utility class to debug binder calls on UI thread

Change-Id: Ic25b788f3f8c9b01b986f148d9d4a568a610f8d5
diff --git a/quickstep/src/com/android/quickstep/util/BinderTracker.java b/quickstep/src/com/android/quickstep/util/BinderTracker.java
new file mode 100644
index 0000000..32d0d53
--- /dev/null
+++ b/quickstep/src/com/android/quickstep/util/BinderTracker.java
@@ -0,0 +1,63 @@
+/*
+ * 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.quickstep.util;
+
+import android.os.Binder;
+import android.os.IBinder;
+import android.os.Looper;
+import android.util.Log;
+
+import com.android.launcher3.config.FeatureFlags;
+
+/**
+ * Utility class to test and check binder calls during development.
+ */
+public class BinderTracker {
+
+    private static final String TAG = "BinderTracker";
+
+    public static void start() {
+        if (!FeatureFlags.IS_DOGFOOD_BUILD) {
+            Log.wtf(TAG, "Accessing tracker in released code.", new Exception());
+            return;
+        }
+
+        Binder.setProxyTransactListener(new Tracker());
+    }
+
+    public static void stop() {
+        if (!FeatureFlags.IS_DOGFOOD_BUILD) {
+            Log.wtf(TAG, "Accessing tracker in released code.", new Exception());
+            return;
+        }
+        Binder.setProxyTransactListener(null);
+    }
+
+    private static class Tracker implements Binder.ProxyTransactListener {
+
+        @Override
+        public Object onTransactStarted(IBinder iBinder, int code) {
+            if (Looper.myLooper() == Looper.getMainLooper()) {
+                Log.e(TAG, "Binder call on ui thread", new Exception());
+            }
+            return null;
+        }
+
+        @Override
+        public void onTransactEnded(Object session) { }
+    }
+}