Add tests for DeferredStartupHandler.

BUG=702154

Change-Id: Ic5b338b9c4a59be0d777b38c6341d9ca293ba9bb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2131152
Commit-Queue: Ted Choc <tedchoc@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: Peter Wen <wnwen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#755937}

chrome/android/chrome_junit_test_java_sources.gni

@@ -2,11 +2,13 @@ chrome_junit_test_java_sources = [
   "junit/src/org/chromium/chrome/browser/AppIndexingUtilTest.java",
   "junit/src/org/chromium/chrome/browser/ChromeActionModeHandlerTest.java",
   "junit/src/org/chromium/chrome/browser/ChromeBackupAgentTest.java",
+  "junit/src/org/chromium/chrome/browser/DeferredStartupHandlerTest.java",
   "junit/src/org/chromium/chrome/browser/DelayedScreenLockIntentHandlerTest.java",
   "junit/src/org/chromium/chrome/browser/DeviceConditionsTest.java",
   "junit/src/org/chromium/chrome/browser/IntentHeadersRecorderTest.java",
   "junit/src/org/chromium/chrome/browser/SSLClientCertificateRequestTest.java",
   "junit/src/org/chromium/chrome/browser/ShadowDeviceConditions.java",
+  "junit/src/org/chromium/chrome/browser/ShadowIdleHandlerAwareMessageQueue.java",
   "junit/src/org/chromium/chrome/browser/ShortcutHelperTest.java",
   "junit/src/org/chromium/chrome/browser/about_settings/AboutSettingsBridgeTest.java",
   "junit/src/org/chromium/chrome/browser/autofill/AutofillUiUtilsTest.java",

chrome/android/java/src/org/chromium/chrome/browser/DeferredStartupHandler.java

@@ -5,12 +5,10 @@
 package org.chromium.chrome.browser;
 
 import android.annotation.SuppressLint;
-import android.content.Context;
 import android.os.Looper;
 
 import androidx.annotation.VisibleForTesting;
 
-import org.chromium.base.ContextUtils;
 import org.chromium.base.ThreadUtils;
 
 import java.util.LinkedList;
@@ -25,8 +23,7 @@ public class DeferredStartupHandler {
         private static final DeferredStartupHandler INSTANCE = new DeferredStartupHandler();
     }
 
-    private boolean mDeferredStartupCompletedForApp;
-    private final Context mAppContext;
+    private Boolean mDeferredStartupCompletedAllPendingTasks;
 
     private final Queue<Runnable> mDeferredTasks;
 
@@ -47,7 +44,6 @@ public class DeferredStartupHandler {
     private static DeferredStartupHandler sDeferredStartupHandler;
 
     protected DeferredStartupHandler() {
-        mAppContext = ContextUtils.getApplicationContext();
         mDeferredTasks = new LinkedList<>();
     }
 
@@ -57,11 +53,18 @@ public class DeferredStartupHandler {
      * tasks.
      */
     public void queueDeferredTasksOnIdleHandler() {
+        // Ensure only a single IdleHandler is added at any given time.
+        if (mDeferredStartupCompletedAllPendingTasks != null
+                && !mDeferredStartupCompletedAllPendingTasks) {
+            return;
+        }
+        mDeferredStartupCompletedAllPendingTasks = false;
+
         Looper.myQueue().addIdleHandler(() -> {
             Runnable currentTask = mDeferredTasks.poll();
             if (currentTask == null) {
-                if (!mDeferredStartupCompletedForApp) {
-                    mDeferredStartupCompletedForApp = true;
+                if (!mDeferredStartupCompletedAllPendingTasks) {
+                    mDeferredStartupCompletedAllPendingTasks = true;
                 }
                 return false;
             }
@@ -86,6 +89,7 @@ public class DeferredStartupHandler {
      */
     @VisibleForTesting
     public boolean isDeferredStartupCompleteForApp() {
-        return mDeferredStartupCompletedForApp;
+        return mDeferredStartupCompletedAllPendingTasks != null
+                && mDeferredStartupCompletedAllPendingTasks;
     }
 }

chrome/android/junit/src/org/chromium/chrome/browser/DeferredStartupHandlerTest.java

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser;
+
+import android.os.Looper;
+import android.os.MessageQueue.IdleHandler;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.annotation.Config;
+import org.robolectric.shadow.api.Shadow;
+
+import org.chromium.base.test.util.CallbackHelper;
+import org.chromium.testing.local.LocalRobolectricTestRunner;
+
+/**
+ * Unit tests for DeferredStartupHandler.
+ */
+@RunWith(LocalRobolectricTestRunner.class)
+@Config(manifest = Config.NONE, shadows = {ShadowIdleHandlerAwareMessageQueue.class})
+public class DeferredStartupHandlerTest {
+    private DeferredStartupHandler mDeferredStartupHandler;
+    private ShadowIdleHandlerAwareMessageQueue mShadowMessageQueue;
+
+    @Before
+    public void setUp() {
+        mShadowMessageQueue = (ShadowIdleHandlerAwareMessageQueue) Shadow.extract(Looper.myQueue());
+        mShadowMessageQueue.clearIdleHandlers();
+        mDeferredStartupHandler = new DeferredStartupHandler();
+    }
+
+    @Test
+    public void addDeferredTask_SingleTask() {
+        CallbackHelper helper = new CallbackHelper();
+        mDeferredStartupHandler.addDeferredTask(() -> helper.notifyCalled());
+
+        Assert.assertEquals(0, helper.getCallCount());
+        Assert.assertEquals(0, mShadowMessageQueue.getIdleHandlers().size());
+
+        mDeferredStartupHandler.queueDeferredTasksOnIdleHandler();
+        Assert.assertEquals(0, helper.getCallCount());
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+
+        mShadowMessageQueue.runIdleHandlers();
+        Assert.assertEquals(1, helper.getCallCount());
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+
+        mShadowMessageQueue.runIdleHandlers();
+        Assert.assertEquals(1, helper.getCallCount());
+        Assert.assertEquals(0, mShadowMessageQueue.getIdleHandlers().size());
+    }
+
+    @Test
+    public void addDeferredTask_MultipleTask() {
+        CallbackHelper helper = new CallbackHelper();
+        mDeferredStartupHandler.addDeferredTask(() -> helper.notifyCalled());
+        mDeferredStartupHandler.addDeferredTask(() -> helper.notifyCalled());
+        mDeferredStartupHandler.addDeferredTask(() -> helper.notifyCalled());
+
+        Assert.assertEquals(0, helper.getCallCount());
+        Assert.assertEquals(0, mShadowMessageQueue.getIdleHandlers().size());
+
+        mDeferredStartupHandler.queueDeferredTasksOnIdleHandler();
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+
+        mShadowMessageQueue.runIdleHandlers();
+        Assert.assertEquals(1, helper.getCallCount());
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+
+        mShadowMessageQueue.runIdleHandlers();
+        Assert.assertEquals(2, helper.getCallCount());
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+
+        mShadowMessageQueue.runIdleHandlers();
+        Assert.assertEquals(3, helper.getCallCount());
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+
+        mShadowMessageQueue.runIdleHandlers();
+        Assert.assertEquals(3, helper.getCallCount());
+        Assert.assertEquals(0, mShadowMessageQueue.getIdleHandlers().size());
+    }
+
+    @Test
+    public void addDeferredTask_WhileIdleHandlerRunning() {
+        CallbackHelper helper = new CallbackHelper();
+        mDeferredStartupHandler.addDeferredTask(() -> helper.notifyCalled());
+
+        Assert.assertEquals(0, helper.getCallCount());
+        Assert.assertEquals(0, mShadowMessageQueue.getIdleHandlers().size());
+
+        mDeferredStartupHandler.queueDeferredTasksOnIdleHandler();
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+
+        mShadowMessageQueue.runIdleHandlers();
+        Assert.assertEquals(1, helper.getCallCount());
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+
+        // Add a new deferred task.
+        mDeferredStartupHandler.addDeferredTask(() -> helper.notifyCalled());
+
+        // The subsequent IdleHandler pass should run the newly added task.
+        mShadowMessageQueue.runIdleHandlers();
+        Assert.assertEquals(2, helper.getCallCount());
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+
+        mShadowMessageQueue.runIdleHandlers();
+        Assert.assertEquals(2, helper.getCallCount());
+        Assert.assertEquals(0, mShadowMessageQueue.getIdleHandlers().size());
+    }
+
+    @Test
+    public void addDeferredTask_AfterIdleHandlerRan() {
+        CallbackHelper helper = new CallbackHelper();
+        mDeferredStartupHandler.addDeferredTask(() -> helper.notifyCalled());
+
+        Assert.assertEquals(0, helper.getCallCount());
+        Assert.assertEquals(0, mShadowMessageQueue.getIdleHandlers().size());
+
+        mDeferredStartupHandler.queueDeferredTasksOnIdleHandler();
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+
+        mShadowMessageQueue.runIdleHandlers();
+        mShadowMessageQueue.runIdleHandlers();
+
+        Assert.assertEquals(1, helper.getCallCount());
+        Assert.assertEquals(0, mShadowMessageQueue.getIdleHandlers().size());
+
+        // Add a new task.
+        CallbackHelper helper2 = new CallbackHelper();
+        mDeferredStartupHandler.addDeferredTask(() -> helper2.notifyCalled());
+        Assert.assertEquals(1, helper.getCallCount());
+        Assert.assertEquals(0, helper2.getCallCount());
+        Assert.assertEquals(0, mShadowMessageQueue.getIdleHandlers().size());
+
+        // Ensure a new request to queue can process these tasks.
+        mDeferredStartupHandler.queueDeferredTasksOnIdleHandler();
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+
+        mShadowMessageQueue.runIdleHandlers();
+        mShadowMessageQueue.runIdleHandlers();
+
+        Assert.assertEquals(1, helper.getCallCount());
+        Assert.assertEquals(1, helper2.getCallCount());
+        Assert.assertEquals(0, mShadowMessageQueue.getIdleHandlers().size());
+    }
+
+    @Test
+    public void queueDeferredTasksOnIdleHandler_OnlyOneIdleHandler() {
+        Assert.assertEquals(0, mShadowMessageQueue.getIdleHandlers().size());
+
+        mDeferredStartupHandler.queueDeferredTasksOnIdleHandler();
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+        IdleHandler initialIdleHandler = mShadowMessageQueue.getIdleHandlers().get(0);
+
+        // Ensure a second call to queueDeferredTasksOnIdleHandler does not add another IdleHandler.
+        mDeferredStartupHandler.queueDeferredTasksOnIdleHandler();
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+        Assert.assertEquals(initialIdleHandler, mShadowMessageQueue.getIdleHandlers().get(0));
+
+        mShadowMessageQueue.runIdleHandlers();
+        mShadowMessageQueue.runIdleHandlers();
+
+        Assert.assertEquals(0, mShadowMessageQueue.getIdleHandlers().size());
+
+        // Ensure a call queueDeferredTasksOnIdleHandler after the previous IdleHandler completes
+        // adds a new IdleHandler.
+        mDeferredStartupHandler.queueDeferredTasksOnIdleHandler();
+        Assert.assertEquals(1, mShadowMessageQueue.getIdleHandlers().size());
+    }
+}

chrome/android/junit/src/org/chromium/chrome/browser/ShadowIdleHandlerAwareMessageQueue.java

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser;
+
+import android.os.MessageQueue;
+import android.os.MessageQueue.IdleHandler;
+
+import org.robolectric.annotation.Implements;
+import org.robolectric.shadows.ShadowLegacyMessageQueue;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Shadow MessageQueue implementation that adds support for IdleHandler(s).
+ */
+@Implements(MessageQueue.class)
+public class ShadowIdleHandlerAwareMessageQueue extends ShadowLegacyMessageQueue {
+    private final List<IdleHandler> mIdleHandlers = new ArrayList<>();
+    private final Object mIdleHandlersLock = new Object();
+
+    /** Default constructor needed by robolectric. */
+    public ShadowIdleHandlerAwareMessageQueue() {}
+
+    /** @see MessageQueue#addIdleHandler(IdleHandler) */
+    public void addIdleHandler(IdleHandler handler) {
+        synchronized (mIdleHandlersLock) {
+            mIdleHandlers.add(handler);
+        }
+    }
+
+    /** @see MessageQueue#removeIdleHandler(IdleHandler) */
+    public void removeIdleHandler(IdleHandler handler) {
+        synchronized (mIdleHandlersLock) {
+            mIdleHandlers.remove(handler);
+        }
+    }
+
+    /**
+     * Run all idle handlers.
+     */
+    public void runIdleHandlers() {
+        List<IdleHandler> idleHandlers;
+        synchronized (mIdleHandlersLock) {
+            idleHandlers = new ArrayList<>(mIdleHandlers);
+        }
+        for (int i = 0; i < idleHandlers.size(); i++) {
+            IdleHandler handler = idleHandlers.get(i);
+            if (!handler.queueIdle()) removeIdleHandler(handler);
+        }
+    }
+
+    public List<IdleHandler> getIdleHandlers() {
+        return mIdleHandlers;
+    }
+
+    public void clearIdleHandlers() {
+        synchronized (mIdleHandlersLock) {
+            mIdleHandlers.clear();
+        }
+    }
+}
\ No newline at end of file