diff --git a/libs/gui/TEST_MAPPING b/libs/gui/TEST_MAPPING
new file mode 100644
index 0000000..1c43530
--- /dev/null
+++ b/libs/gui/TEST_MAPPING
@@ -0,0 +1,7 @@
+{
+  "imports": [
+    {
+      "path": "frameworks/native/libs/nativewindow"
+    }
+  ]
+}
diff --git a/libs/nativewindow/ANativeWindow.cpp b/libs/nativewindow/ANativeWindow.cpp
index 1751443..4c59e6c 100644
--- a/libs/nativewindow/ANativeWindow.cpp
+++ b/libs/nativewindow/ANativeWindow.cpp
@@ -266,3 +266,11 @@
 int ANativeWindow_setAutoPrerotation(ANativeWindow* window, bool autoPrerotation) {
     return native_window_set_auto_prerotation(window, autoPrerotation);
 }
+
+/**************************************************************************************************
+ * apex-stable
+ **************************************************************************************************/
+
+int ANativeWindow_getLastDequeueDuration(ANativeWindow* window) {
+    return query(window, NATIVE_WINDOW_LAST_DEQUEUE_DURATION);
+}
diff --git a/libs/nativewindow/TEST_MAPPING b/libs/nativewindow/TEST_MAPPING
new file mode 100644
index 0000000..3d7f3c2
--- /dev/null
+++ b/libs/nativewindow/TEST_MAPPING
@@ -0,0 +1,7 @@
+{
+  "presubmit": [
+    {
+      "name": "libnativewindow_test"
+    }
+  ]
+}
diff --git a/libs/nativewindow/include/apex/window.h b/libs/nativewindow/include/apex/window.h
new file mode 100644
index 0000000..0260cbc
--- /dev/null
+++ b/libs/nativewindow/include/apex/window.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright 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.
+ */
+
+#pragma once
+
+#include <nativebase/nativebase.h>
+
+// apex is a superset of the NDK
+#include <android/native_window.h>
+
+__BEGIN_DECLS
+
+/**
+ * Retrieves how long it took for the last time a buffer was dequeued.
+ *
+ * \return a negative value on error, otherwise returns the duration in
+ * microseconds.
+ */
+int ANativeWindow_getLastDequeueDuration(ANativeWindow* window);
+
+__END_DECLS
diff --git a/libs/nativewindow/include/system/window.h b/libs/nativewindow/include/system/window.h
index 8cbf0a4..78354bb 100644
--- a/libs/nativewindow/include/system/window.h
+++ b/libs/nativewindow/include/system/window.h
@@ -41,7 +41,8 @@
 #include <unistd.h>
 #include <stdbool.h>
 
-// system/window.h is a superset of the vndk
+// system/window.h is a superset of the vndk and apex apis
+#include <apex/window.h>
 #include <vndk/window.h>
 
 
diff --git a/libs/nativewindow/libnativewindow.map.txt b/libs/nativewindow/libnativewindow.map.txt
index 119a07d..7fe4df0 100644
--- a/libs/nativewindow/libnativewindow.map.txt
+++ b/libs/nativewindow/libnativewindow.map.txt
@@ -22,6 +22,7 @@
     ANativeWindow_getBuffersDataSpace; # introduced=28
     ANativeWindow_getFormat;
     ANativeWindow_getHeight;
+    ANativeWindow_getLastDequeueDuration; # apex # introduced=30
     ANativeWindow_getWidth;
     ANativeWindow_lock;
     ANativeWindow_query; # vndk
diff --git a/libs/nativewindow/tests/ANativeWindowTest.cpp b/libs/nativewindow/tests/ANativeWindowTest.cpp
new file mode 100644
index 0000000..a80da24
--- /dev/null
+++ b/libs/nativewindow/tests/ANativeWindowTest.cpp
@@ -0,0 +1,72 @@
+/*
+ * Copyright 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.
+ */
+
+#define LOG_TAG "ANativeWindow_test"
+//#define LOG_NDEBUG 0
+
+#include <gtest/gtest.h>
+#include <gui/BufferItemConsumer.h>
+#include <gui/BufferQueue.h>
+#include <gui/Surface.h>
+#include <log/log.h>
+#include <sync/sync.h>
+// We need to use the private system apis since not everything is visible to
+// apexes yet.
+#include <system/window.h>
+
+using namespace android;
+
+class ANativeWindowTest : public ::testing::Test {
+protected:
+    void SetUp() override {
+        const ::testing::TestInfo* const test_info =
+                ::testing::UnitTest::GetInstance()->current_test_info();
+        ALOGV("**** Setting up for %s.%s\n", test_info->test_case_name(), test_info->name());
+        BufferQueue::createBufferQueue(&mProducer, &mConsumer);
+        mItemConsumer = new BufferItemConsumer(mConsumer, GRALLOC_USAGE_SW_READ_OFTEN);
+        mWindow = new Surface(mProducer);
+        const int success = native_window_api_connect(mWindow.get(), NATIVE_WINDOW_API_CPU);
+        EXPECT_EQ(0, success);
+    }
+
+    void TearDown() override {
+        const ::testing::TestInfo* const test_info =
+                ::testing::UnitTest::GetInstance()->current_test_info();
+        ALOGV("**** Tearing down after %s.%s\n", test_info->test_case_name(), test_info->name());
+        const int success = native_window_api_disconnect(mWindow.get(), NATIVE_WINDOW_API_CPU);
+        EXPECT_EQ(0, success);
+    }
+    sp<IGraphicBufferProducer> mProducer;
+    sp<IGraphicBufferConsumer> mConsumer;
+    sp<BufferItemConsumer> mItemConsumer;
+    sp<ANativeWindow> mWindow;
+};
+
+TEST_F(ANativeWindowTest, getLastDequeueDuration_noDequeue_returnsZero) {
+    int result = ANativeWindow_getLastDequeueDuration(mWindow.get());
+    EXPECT_EQ(0, result);
+}
+
+TEST_F(ANativeWindowTest, getLastDequeueDuration_withDequeue_returnsTime) {
+    ANativeWindowBuffer* buffer;
+    int fd;
+    int result = ANativeWindow_dequeueBuffer(mWindow.get(), &buffer, &fd);
+    close(fd);
+    EXPECT_EQ(0, result);
+
+    result = ANativeWindow_getLastDequeueDuration(mWindow.get());
+    EXPECT_GT(result, 0);
+}
diff --git a/libs/nativewindow/tests/Android.bp b/libs/nativewindow/tests/Android.bp
index 20071be..cdb3d20 100644
--- a/libs/nativewindow/tests/Android.bp
+++ b/libs/nativewindow/tests/Android.bp
@@ -15,13 +15,22 @@
 //
 
 cc_test {
-    name: "AHardwareBufferTest",
+    name: "libnativewindow_test",
+    test_suites: [
+        "device-tests",
+    ],
     shared_libs: [
+        "libgui",
+        "liblog",
         "libnativewindow",
+        "libsync",
+        "libutils",
         "android.hardware.graphics.common@1.0",
     ],
     srcs: [
         "AHardwareBufferTest.cpp",
-        "c_compatibility.c"],
+        "ANativeWindowTest.cpp",
+        "c_compatibility.c",
+    ],
     cflags: ["-Wall", "-Werror"],
 }
diff --git a/libs/nativewindow/tests/c_compatibility.c b/libs/nativewindow/tests/c_compatibility.c
index befd88f..aa9b4f7 100644
--- a/libs/nativewindow/tests/c_compatibility.c
+++ b/libs/nativewindow/tests/c_compatibility.c
@@ -16,6 +16,7 @@
 
 #include <android/hardware_buffer.h>
 #include <android/native_window.h>
+#include <apex/window.h>
 #include <vndk/hardware_buffer.h>
 #include <vndk/window.h>