Add UserInputTracker, which keeps track of recent user input events.

chrome/browser/page_load_metrics/user_input_tracker_unittest.cc

+// Copyright (c) 2015 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/page_load_metrics/user_input_tracker.h"
+
+#include "base/time/time.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/WebKit/public/platform/WebInputEvent.h"
+
+namespace {
+
+// UserInputTracker allows events to be at most 2 seconds old. Thus we use
+// 2100ms to make sure the age is greater than 2 seconds.
+const int kTooOldMilliseconds = 2100;
+
+double ToMonotonicallyIncreasingSeconds(base::TimeTicks t) {
+  return t.ToInternalValue() /
+         static_cast<double>(base::Time::kMicrosecondsPerSecond);
+}
+
+class FakeInputEvent : public blink::WebInputEvent {
+ public:
+  FakeInputEvent() : WebInputEvent(sizeof(FakeInputEvent)) {
+    timeStampSeconds = ToMonotonicallyIncreasingSeconds(base::TimeTicks::Now());
+    type = blink::WebInputEvent::Char;
+  }
+
+  base::TimeTicks GetTimeStamp() {
+    return page_load_metrics::UserInputTracker::GetEventTime(*this);
+  }
+};
+
+}  // namespace
+
+class UserInputTrackerTest : public testing::Test {};
+
+TEST_F(UserInputTrackerTest, Basic) {
+  page_load_metrics::UserInputTracker tracker;
+  ASSERT_EQ(base::TimeTicks(),
+            tracker.FindMostRecentUserInputEventBefore(base::TimeTicks()));
+  ASSERT_EQ(base::TimeTicks(),
+            tracker.FindMostRecentUserInputEventBefore(base::TimeTicks::Now()));
+}
+
+TEST_F(UserInputTrackerTest, SingleEvent) {
+  page_load_metrics::UserInputTracker tracker;
+  FakeInputEvent e;
+  tracker.OnInputEvent(e);
+
+  ASSERT_EQ(base::TimeTicks(),
+            tracker.FindMostRecentUserInputEventBefore(e.GetTimeStamp()));
+
+  base::TimeTicks after =
+      e.GetTimeStamp() + base::TimeDelta::FromMicroseconds(1);
+
+  ASSERT_EQ(e.GetTimeStamp(),
+            tracker.FindMostRecentUserInputEventBefore(after));
+
+  tracker.ConsumeUserInputEventsUpTo(e.GetTimeStamp());
+
+  ASSERT_EQ(base::TimeTicks(),
+            tracker.FindMostRecentUserInputEventBefore(after));
+}
+
+TEST_F(UserInputTrackerTest, MultipleEvents) {
+  page_load_metrics::UserInputTracker tracker;
+  FakeInputEvent e1;
+  FakeInputEvent e2;
+
+  // Make sure that the two events are monotonically increasing, and that both
+  // are in the past.
+  e1.timeStampSeconds = ToMonotonicallyIncreasingSeconds(
+      e2.GetTimeStamp() - base::TimeDelta::FromMicroseconds(1));
+  tracker.OnInputEvent(e1);
+  tracker.OnInputEvent(e2);
+
+  ASSERT_EQ(base::TimeTicks(),
+            tracker.FindMostRecentUserInputEventBefore(e1.GetTimeStamp()));
+  ASSERT_EQ(e1.GetTimeStamp(),
+            tracker.FindMostRecentUserInputEventBefore(e2.GetTimeStamp()));
+
+  base::TimeTicks after =
+      e2.GetTimeStamp() + base::TimeDelta::FromMicroseconds(1);
+  ASSERT_EQ(e2.GetTimeStamp(),
+            tracker.FindMostRecentUserInputEventBefore(after));
+
+  tracker.ConsumeUserInputEventsUpTo(e1.GetTimeStamp());
+  ASSERT_EQ(base::TimeTicks(),
+            tracker.FindMostRecentUserInputEventBefore(e1.GetTimeStamp()));
+  ASSERT_EQ(base::TimeTicks(),
+            tracker.FindMostRecentUserInputEventBefore(e2.GetTimeStamp()));
+  ASSERT_EQ(e2.GetTimeStamp(),
+            tracker.FindMostRecentUserInputEventBefore(after));
+
+  tracker.ConsumeUserInputEventsUpTo(e2.GetTimeStamp());
+  ASSERT_EQ(base::TimeTicks(),
+            tracker.FindMostRecentUserInputEventBefore(e1.GetTimeStamp()));
+  ASSERT_EQ(base::TimeTicks(),
+            tracker.FindMostRecentUserInputEventBefore(e2.GetTimeStamp()));
+  ASSERT_EQ(base::TimeTicks(),
+            tracker.FindMostRecentUserInputEventBefore(after));
+
+  tracker.OnInputEvent(e1);
+  tracker.OnInputEvent(e2);
+  ASSERT_EQ(e2.GetTimeStamp(),
+            tracker.FindMostRecentUserInputEventBefore(after));
+  tracker.ConsumeUserInputEventsUpTo(e2.GetTimeStamp());
+  ASSERT_EQ(base::TimeTicks(),
+            tracker.FindMostRecentUserInputEventBefore(after));
+}
+
+TEST_F(UserInputTrackerTest, ExcludeOldEvents) {
+  page_load_metrics::UserInputTracker tracker;
+  FakeInputEvent e1;
+  FakeInputEvent e2;
+  // make sure e1 is too old to be considered.
+  e1.timeStampSeconds = ToMonotonicallyIncreasingSeconds(
+      e2.GetTimeStamp() -
+      base::TimeDelta::FromMilliseconds(kTooOldMilliseconds));
+
+  tracker.OnInputEvent(e1);
+  tracker.OnInputEvent(e2);
+
+  ASSERT_EQ(base::TimeTicks(),
+            tracker.FindMostRecentUserInputEventBefore(
+                e1.GetTimeStamp() + base::TimeDelta::FromMilliseconds(1)));
+  ASSERT_EQ(base::TimeTicks(),
+            tracker.FindMostRecentUserInputEventBefore(
+                e2.GetTimeStamp() +
+                base::TimeDelta::FromMilliseconds(kTooOldMilliseconds)));
+  ASSERT_EQ(e2.GetTimeStamp(),
+            tracker.FindMostRecentUserInputEventBefore(
+                e2.GetTimeStamp() + base::TimeDelta::FromMilliseconds(1)));
+}