Add desktop engagement metrics.

chrome/browser/metrics/desktop_engagement/desktop_engagement_service_unittest.cc

+// Copyright 2016 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.
+
+#include "chrome/browser/metrics/desktop_engagement/desktop_engagement_service.h"
+
+#include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "base/test/histogram_tester.h"
+#include "base/test/test_mock_time_task_runner.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+// Mock class for |DesktopEngagementService| for testing.
+class MockDesktopEngagementService : public DesktopEngagementService {
+ public:
+  bool IsVisible() { return is_visible_; }
+

[Alexei Svitkine (slow), 2016/07/26 19:20:37]

Nit: You can omit newlines for these simple accessors. Also, use hacker_style.

[gayane -on leave until 09-2017, 2016/07/26 21:41:19]

Done.

+  bool InSession() { return in_session_; }
+
+  bool IsAudioPlaying() { return is_audio_playing_; }
+
+  bool IsTimeOut() { return time_out_; }
+
+  void SetInactivityTimeout(int seconds) {
+    inactivity_timeout_ = base::TimeDelta::FromSeconds(seconds);
+  }
+
+ protected:
+  void OnTimerFired() override {
+    DesktopEngagementService::OnTimerFired();
+    time_out_ = true;
+  }
+
+ private:
+  bool time_out_ = false;
+};
+
+TEST(DesktopEngagementServiceTest, TestVisibility) {
+  base::MessageLoop loop(base::MessageLoop::TYPE_DEFAULT);
+  base::HistogramTester histogram_tester;
+
+  MockDesktopEngagementService instance;
+
+  // The browser becomes visible but it shouldn't start the session.
+  instance.OnVisibilityChanged(true);
+  EXPECT_FALSE(instance.InSession());
+  EXPECT_TRUE(instance.IsVisible());
+  EXPECT_FALSE(instance.IsAudioPlaying());
+  histogram_tester.ExpectTotalCount("Session.TotalDuration", 0);
+
+  instance.OnUserEvent();
+  EXPECT_TRUE(instance.InSession());
+  EXPECT_TRUE(instance.IsVisible());
+  EXPECT_FALSE(instance.IsAudioPlaying());
+  histogram_tester.ExpectTotalCount("Session.TotalDuration", 0);
+
+  // Even if there is a recent user event visibility change should end the
+  // session.
+  instance.OnUserEvent();
+  instance.OnUserEvent();
+  instance.OnVisibilityChanged(false);
+  EXPECT_FALSE(instance.InSession());
+  EXPECT_FALSE(instance.IsVisible());
+  EXPECT_FALSE(instance.IsAudioPlaying());
+  histogram_tester.ExpectTotalCount("Session.TotalDuration", 1);
+
+  // For the second time only visibility change should start the session.
+  instance.OnVisibilityChanged(true);
+  EXPECT_TRUE(instance.InSession());
+  EXPECT_TRUE(instance.IsVisible());
+  EXPECT_FALSE(instance.IsAudioPlaying());
+  histogram_tester.ExpectTotalCount("Session.TotalDuration", 1);
+  instance.OnVisibilityChanged(false);
+  EXPECT_FALSE(instance.InSession());
+  EXPECT_FALSE(instance.IsVisible());
+  EXPECT_FALSE(instance.IsAudioPlaying());
+  histogram_tester.ExpectTotalCount("Session.TotalDuration", 2);
+}
+
+TEST(DesktopEngagementServiceTest, TestUserEvent) {
+  base::MessageLoop loop(base::MessageLoop::TYPE_DEFAULT);
+  base::HistogramTester histogram_tester;
+
+  MockDesktopEngagementService instance;
+  instance.SetInactivityTimeout(1);
+
+  EXPECT_FALSE(instance.InSession());
+  EXPECT_FALSE(instance.IsVisible());
+  EXPECT_FALSE(instance.IsAudioPlaying());
+  histogram_tester.ExpectTotalCount("Session.TotalDuration", 0);
+
+  // User event doesn't go through if nothing is visible.
+  instance.OnUserEvent();
+  EXPECT_FALSE(instance.InSession());
+  EXPECT_FALSE(instance.IsVisible());
+  EXPECT_FALSE(instance.IsAudioPlaying());
+  histogram_tester.ExpectTotalCount("Session.TotalDuration", 0);
+
+  instance.OnVisibilityChanged(true);
+  instance.OnUserEvent();
+  EXPECT_TRUE(instance.InSession());
+  EXPECT_TRUE(instance.IsVisible());
+  EXPECT_FALSE(instance.IsAudioPlaying());
+  histogram_tester.ExpectTotalCount("Session.TotalDuration", 0);
+
+  // Wait until the session expires.
+  while (!instance.IsTimeOut()) {
+    base::RunLoop().RunUntilIdle();
+  }
+
+  EXPECT_FALSE(instance.InSession());
+  EXPECT_TRUE(instance.IsVisible());
+  EXPECT_FALSE(instance.IsAudioPlaying());
+  histogram_tester.ExpectTotalCount("Session.TotalDuration", 1);
+}
+
+TEST(DesktopEngagementServiceTest, TestAudioEvent) {
+  base::MessageLoop loop(base::MessageLoop::TYPE_DEFAULT);
+  base::HistogramTester histogram_tester;
+
+  MockDesktopEngagementService instance;
+  instance.SetInactivityTimeout(1);
+
+  instance.OnVisibilityChanged(true);
+  instance.OnAudioStart();
+  EXPECT_TRUE(instance.InSession());
+  EXPECT_TRUE(instance.IsVisible());
+  EXPECT_TRUE(instance.IsAudioPlaying());
+  histogram_tester.ExpectTotalCount("Session.TotalDuration", 0);
+
+  instance.OnVisibilityChanged(false);
+  EXPECT_TRUE(instance.InSession());
+  EXPECT_FALSE(instance.IsVisible());
+  EXPECT_TRUE(instance.IsAudioPlaying());
+  histogram_tester.ExpectTotalCount("Session.TotalDuration", 0);
+
+  instance.OnAudioEnd();
+  EXPECT_TRUE(instance.InSession());
+  EXPECT_FALSE(instance.IsVisible());
+  EXPECT_FALSE(instance.IsAudioPlaying());
+  histogram_tester.ExpectTotalCount("Session.TotalDuration", 0);
+
+  // Wait until the session expires.
+  while (!instance.IsTimeOut()) {
+    base::RunLoop().RunUntilIdle();
+  }
+
+  EXPECT_FALSE(instance.InSession());
+  EXPECT_FALSE(instance.IsVisible());
+  EXPECT_FALSE(instance.IsAudioPlaying());
+  histogram_tester.ExpectTotalCount("Session.TotalDuration", 1);
+}