Clean-up: Break sampler classes into their own files.

content/browser/media/capture/smooth_event_sampler_unittest.cc

-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// 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 "content/browser/media/capture/video_capture_oracle.h"
+#include "content/browser/media/capture/smooth_event_sampler.h"
 
-#include <cstdlib>
-#include <utility>
-#include <vector>
-
-#include "base/logging.h"
 #include "base/strings/stringprintf.h"
-#include "base/time/time.h"
 #include "testing/gtest/include/gtest/gtest.h"
-#include "ui/gfx/geometry/rect.h"
 
 namespace content {
+
 namespace {
 
 bool AddEventAndConsiderSampling(SmoothEventSampler* sampler,
                                  base::TimeTicks event_time) {
   sampler->ConsiderPresentationEvent(event_time);
   return sampler->ShouldSample();
 }
 
 void SteadyStateSampleAndAdvance(base::TimeDelta vsync,
                                  SmoothEventSampler* sampler,
@@ skipping 404 matching lines @@
     { true, 33.441 }, { false, 0 }, { true, 33.44 }, { false, 16.72 },
     { true, 33.44 }, { false, 0 }, { true, 16.721 }, { true, 50.161 },
     { false, 0 }, { true, 16.72 }, { true, 33.44 }, { false, 0 },
     { true, 33.441 }, { false, 16.72 }, { true, 16.72 }, { true, 50.16 }
   };
 
   SmoothEventSampler sampler(base::TimeDelta::FromSeconds(1) / 30, 3);
   ReplayCheckingSamplerDecisions(data_points, arraysize(data_points), &sampler);
 }
 
-class AnimatedContentSamplerTest : public ::testing::Test {
- public:
-  AnimatedContentSamplerTest() {}
-  ~AnimatedContentSamplerTest() override {}
-
-  void SetUp() override {
-    const base::TimeDelta since_epoch =
-        InitialTestTimeTicks() - base::TimeTicks::UnixEpoch();
-    rand_seed_ = abs(static_cast<int>(since_epoch.InMicroseconds()));
-    sampler_.reset(new AnimatedContentSampler(GetMinCapturePeriod()));
-  }
-
- protected:
-  // Overridden by subclass for parameterized tests.
-  virtual base::TimeDelta GetMinCapturePeriod() const {
-    return base::TimeDelta::FromSeconds(1) / 30;
-  }
-
-  AnimatedContentSampler* sampler() const {
-    return sampler_.get();
-  }
-
-  int GetRandomInRange(int begin, int end) {
-    const int len = end - begin;
-    const int rand_offset = (len == 0) ? 0 : (NextRandomInt() % (end - begin));
-    return begin + rand_offset;
-  }
-
-  gfx::Rect GetRandomDamageRect() {
-    return gfx::Rect(0, 0, GetRandomInRange(1, 100), GetRandomInRange(1, 100));
-  }
-
-  gfx::Rect GetContentDamageRect() {
-    // This must be distinct from anything GetRandomDamageRect() could return.
-    return gfx::Rect(0, 0, 1280, 720);
-  }
-
-  // Directly inject an observation.  Only used to test
-  // ElectMajorityDamageRect().
-  void ObserveDamageRect(const gfx::Rect& damage_rect) {
-    sampler_->observations_.push_back(
-        AnimatedContentSampler::Observation(damage_rect, base::TimeTicks()));
-  }
-
-  gfx::Rect ElectMajorityDamageRect() const {
-    return sampler_->ElectMajorityDamageRect();
-  }
-
- private:
-  // Note: Not using base::RandInt() because it is horribly slow on debug
-  // builds.  The following is a very simple, deterministic LCG:
-  int NextRandomInt() {
-    rand_seed_ = (1103515245 * rand_seed_ + 12345) % (1 << 31);
-    return rand_seed_;
-  }
-
-  int rand_seed_;
-  scoped_ptr<AnimatedContentSampler> sampler_;
-};
-
-TEST_F(AnimatedContentSamplerTest, ElectsNoneFromZeroDamageRects) {
-  EXPECT_EQ(gfx::Rect(), ElectMajorityDamageRect());
-}
-
-TEST_F(AnimatedContentSamplerTest, ElectsMajorityFromOneDamageRect) {
-  const gfx::Rect the_one_rect(0, 0, 1, 1);
-  ObserveDamageRect(the_one_rect);
-  EXPECT_EQ(the_one_rect, ElectMajorityDamageRect());
-}
-
-TEST_F(AnimatedContentSamplerTest, ElectsNoneFromTwoDamageRectsOfSameArea) {
-  const gfx::Rect one_rect(0, 0, 1, 1);
-  const gfx::Rect another_rect(1, 1, 1, 1);
-  ObserveDamageRect(one_rect);
-  ObserveDamageRect(another_rect);
-  EXPECT_EQ(gfx::Rect(), ElectMajorityDamageRect());
-}
-
-TEST_F(AnimatedContentSamplerTest, ElectsLargerOfTwoDamageRects_1) {
-  const gfx::Rect one_rect(0, 0, 1, 1);
-  const gfx::Rect another_rect(0, 0, 2, 2);
-  ObserveDamageRect(one_rect);
-  ObserveDamageRect(another_rect);
-  EXPECT_EQ(another_rect, ElectMajorityDamageRect());
-}
-
-TEST_F(AnimatedContentSamplerTest, ElectsLargerOfTwoDamageRects_2) {
-  const gfx::Rect one_rect(0, 0, 2, 2);
-  const gfx::Rect another_rect(0, 0, 1, 1);
-  ObserveDamageRect(one_rect);
-  ObserveDamageRect(another_rect);
-  EXPECT_EQ(one_rect, ElectMajorityDamageRect());
-}
-
-TEST_F(AnimatedContentSamplerTest, ElectsSameAsMooreDemonstration) {
-  // A more complex sequence (from Moore's web site): Three different Rects with
-  // the same area, but occurring a different number of times.  C should win the
-  // vote.
-  const gfx::Rect rect_a(0, 0, 1, 4);
-  const gfx::Rect rect_b(1, 1, 4, 1);
-  const gfx::Rect rect_c(2, 2, 2, 2);
-  for (int i = 0; i < 3; ++i)
-    ObserveDamageRect(rect_a);
-  for (int i = 0; i < 2; ++i)
-    ObserveDamageRect(rect_c);
-  for (int i = 0; i < 2; ++i)
-    ObserveDamageRect(rect_b);
-  for (int i = 0; i < 3; ++i)
-    ObserveDamageRect(rect_c);
-  ObserveDamageRect(rect_b);
-  for (int i = 0; i < 2; ++i)
-    ObserveDamageRect(rect_c);
-  EXPECT_EQ(rect_c, ElectMajorityDamageRect());
-}
-
-TEST_F(AnimatedContentSamplerTest, Elects24FpsVideoInsteadOf48FpsSpinner) {
-  // Scenario: 24 FPS 720x480 Video versus 48 FPS 96x96 "Busy Spinner"
-  const gfx::Rect video_rect(100, 100, 720, 480);
-  const gfx::Rect spinner_rect(360, 0, 96, 96);
-  for (int i = 0; i < 100; ++i) {
-    // |video_rect| occurs once for every two |spinner_rect|.  Vary the order
-    // of events between the two:
-    ObserveDamageRect(video_rect);
-    ObserveDamageRect(spinner_rect);
-    ObserveDamageRect(spinner_rect);
-    ObserveDamageRect(video_rect);
-    ObserveDamageRect(spinner_rect);
-    ObserveDamageRect(spinner_rect);
-    ObserveDamageRect(spinner_rect);
-    ObserveDamageRect(video_rect);
-    ObserveDamageRect(spinner_rect);
-    ObserveDamageRect(spinner_rect);
-    ObserveDamageRect(video_rect);
-    ObserveDamageRect(spinner_rect);
-  }
-  EXPECT_EQ(video_rect, ElectMajorityDamageRect());
-}
-
-namespace {
-
-// A test scenario for AnimatedContentSamplerParameterizedTest.
-struct Scenario {
-  base::TimeDelta vsync_interval;  // Reflects compositor's update rate.
-  base::TimeDelta min_capture_period;  // Reflects maximum capture rate.
-  base::TimeDelta content_period;  // Reflects content animation rate.
-
-  Scenario(base::TimeDelta v, base::TimeDelta m, base::TimeDelta c)
-      : vsync_interval(v), min_capture_period(m), content_period(c) {
-    CHECK(content_period >= vsync_interval)
-        << "Bad test params: Impossible to animate faster than the compositor.";
-  }
-};
-
-// Value printer for Scenario.
-::std::ostream& operator<<(::std::ostream& os, const Scenario& s) {
-  return os << "{ vsync_interval=" << s.vsync_interval.InMicroseconds()
-            << ", min_capture_period=" << s.min_capture_period.InMicroseconds()
-            << ", content_period=" << s.content_period.InMicroseconds()
-            << " }";
-}
-
-base::TimeDelta FpsAsPeriod(int frame_rate) {
-  return base::TimeDelta::FromSeconds(1) / frame_rate;
-}
-
-}  // namespace
-
-class AnimatedContentSamplerParameterizedTest
-    : public AnimatedContentSamplerTest,
-      public ::testing::WithParamInterface<Scenario> {
- public:
-  AnimatedContentSamplerParameterizedTest()
-      : count_dropped_frames_(0), count_sampled_frames_(0) {}
-  virtual ~AnimatedContentSamplerParameterizedTest() {}
-
- protected:
-  typedef std::pair<gfx::Rect, base::TimeTicks> Event;
-
-  base::TimeDelta GetMinCapturePeriod() const override {
-    return GetParam().min_capture_period;
-  }
-
-  // Generate a sequence of events from the compositor pipeline.  The event
-  // times will all be at compositor vsync boundaries.
-  std::vector<Event> GenerateEventSequence(base::TimeTicks begin,
-                                           base::TimeTicks end,
-                                           bool include_content_frame_events,
-                                           bool include_random_events) {
-    DCHECK(GetParam().content_period >= GetParam().vsync_interval);
-    base::TimeTicks next_content_time = begin - GetParam().content_period;
-    std::vector<Event> events;
-    for (base::TimeTicks compositor_time = begin; compositor_time < end;
-         compositor_time += GetParam().vsync_interval) {
-      if (include_content_frame_events && next_content_time < compositor_time) {
-        events.push_back(Event(GetContentDamageRect(), compositor_time));
-        next_content_time += GetParam().content_period;
-      } else if (include_random_events && GetRandomInRange(0, 1) == 0) {
-        events.push_back(Event(GetRandomDamageRect(), compositor_time));
-      }
-    }
-
-    DCHECK(!events.empty());
-    return events;
-  }
-
-  // Feed |events| through the sampler, and detect whether the expected
-  // lock-in/out transition occurs.  Also, track and measure the frame drop
-  // ratio and check it against the expected drop rate.
-  void RunEventSequence(const std::vector<Event> events,
-                        bool was_detecting_before,
-                        bool is_detecting_after,
-                        bool simulate_pipeline_back_pressure) {
-    gfx::Rect first_detected_region;
-
-    EXPECT_EQ(was_detecting_before, sampler()->HasProposal());
-    bool has_detection_switched = false;
-    ResetFrameCounters();
-    for (std::vector<Event>::const_iterator i = events.begin();
-         i != events.end(); ++i) {
-      sampler()->ConsiderPresentationEvent(i->first, i->second);
-
-      // Detect when the sampler locks in/out, and that it stays that way for
-      // all further iterations of this loop.
-      if (!has_detection_switched &&
-          was_detecting_before != sampler()->HasProposal()) {
-        has_detection_switched = true;
-      }
-      ASSERT_EQ(
-          has_detection_switched ? is_detecting_after : was_detecting_before,
-          sampler()->HasProposal());
-
-      if (sampler()->HasProposal()) {
-        // Make sure the sampler doesn't flip-flop and keep proposing sampling
-        // based on locking into different regions.
-        if (first_detected_region.IsEmpty()) {
-          first_detected_region = sampler()->detected_region();
-          ASSERT_FALSE(first_detected_region.IsEmpty());
-        } else {
-          EXPECT_EQ(first_detected_region, sampler()->detected_region());
-        }
-
-        if (simulate_pipeline_back_pressure && GetRandomInRange(0, 2) == 0)
-          ClientCannotSampleFrame(*i);
-        else
-          ClientDoesWhatSamplerProposes(*i);
-      } else {
-        EXPECT_FALSE(sampler()->ShouldSample());
-        if (!simulate_pipeline_back_pressure || GetRandomInRange(0, 2) == 1)
-          sampler()->RecordSample(i->second);
-      }
-    }
-    EXPECT_EQ(is_detecting_after, sampler()->HasProposal());
-    ExpectFrameDropRatioIsCorrect();
-  }
-
-  void ResetFrameCounters() {
-    count_dropped_frames_ = 0;
-    count_sampled_frames_ = 0;
-  }
-
-  // Keep track what the sampler is proposing, and call RecordSample() if it
-  // proposes sampling |event|.
-  void ClientDoesWhatSamplerProposes(const Event& event) {
-    if (sampler()->ShouldSample()) {
-      EXPECT_EQ(GetContentDamageRect(), event.first);
-      sampler()->RecordSample(sampler()->frame_timestamp());
-      ++count_sampled_frames_;
-    } else if (event.first == GetContentDamageRect()) {
-      ++count_dropped_frames_;
-    }
-  }
-
-  // RecordSample() is not called, but for testing, keep track of what the
-  // sampler is proposing for |event|.
-  void ClientCannotSampleFrame(const Event& event) {
-    if (sampler()->ShouldSample()) {
-      EXPECT_EQ(GetContentDamageRect(), event.first);
-      ++count_sampled_frames_;
-    } else if (event.first == GetContentDamageRect()) {
-      ++count_dropped_frames_;
-    }
-  }
-
-  // Confirm the AnimatedContentSampler is not dropping more frames than
-  // expected, given current test parameters.
-  void ExpectFrameDropRatioIsCorrect() {
-    if (count_sampled_frames_ == 0) {
-      EXPECT_EQ(0, count_dropped_frames_);
-      return;
-    }
-    const double content_framerate =
-        1000000.0 / GetParam().content_period.InMicroseconds();
-    const double capture_framerate =
-        1000000.0 / GetParam().min_capture_period.InMicroseconds();
-    const double expected_drop_rate = std::max(
-        0.0, (content_framerate - capture_framerate) / capture_framerate);
-    const double actual_drop_rate =
-        static_cast<double>(count_dropped_frames_) / count_sampled_frames_;
-    EXPECT_NEAR(expected_drop_rate, actual_drop_rate, 0.015);
-  }
-
- private:
-  // These counters only include the frames with the desired content.
-  int count_dropped_frames_;
-  int count_sampled_frames_;
-};
-
-// Tests that the implementation locks in/out of frames containing stable
-// animated content, whether or not random events are also simultaneously
-// present.
-TEST_P(AnimatedContentSamplerParameterizedTest, DetectsAnimatedContent) {
-  // |begin| refers to the start of an event sequence in terms of the
-  // Compositor's clock.
-  base::TimeTicks begin = InitialTestTimeTicks();
-
-  // Provide random events and expect no lock-in.
-  base::TimeTicks end = begin + base::TimeDelta::FromSeconds(5);
-  RunEventSequence(GenerateEventSequence(begin, end, false, true),
-                   false,
-                   false,
-                   false);
-  begin = end;
-
-  // Provide content frame events with some random events mixed-in, and expect
-  // the sampler to lock-in.
-  end = begin + base::TimeDelta::FromSeconds(5);
-  RunEventSequence(GenerateEventSequence(begin, end, true, true),
-                   false,
-                   true,
-                   false);
-  begin = end;
-
-  // Continue providing content frame events without the random events mixed-in
-  // and expect the lock-in to hold.
-  end = begin + base::TimeDelta::FromSeconds(5);
-  RunEventSequence(GenerateEventSequence(begin, end, true, false),
-                   true,
-                   true,
-                   false);
-  begin = end;
-
-  // Continue providing just content frame events and expect the lock-in to
-  // hold.  Also simulate the capture pipeline experiencing back pressure.
-  end = begin + base::TimeDelta::FromSeconds(20);
-  RunEventSequence(GenerateEventSequence(begin, end, true, false),
-                   true,
-                   true,
-                   true);
-  begin = end;
-
-  // Provide a half-second of random events only, and expect the lock-in to be
-  // broken.
-  end = begin + base::TimeDelta::FromMilliseconds(500);
-  RunEventSequence(GenerateEventSequence(begin, end, false, true),
-                   true,
-                   false,
-                   false);
-  begin = end;
-
-  // Now, go back to providing content frame events, and expect the sampler to
-  // lock-in once again.
-  end = begin + base::TimeDelta::FromSeconds(5);
-  RunEventSequence(GenerateEventSequence(begin, end, true, false),
-                   false,
-                   true,
-                   false);
-  begin = end;
-}
-
-// Tests that AnimatedContentSampler won't lock in to, nor flip-flop between,
-// two animations of the same pixel change rate.  VideoCaptureOracle should
-// revert to using the SmoothEventSampler for these kinds of situations, as
-// there is no "right answer" as to which animation to lock into.
-TEST_P(AnimatedContentSamplerParameterizedTest,
-       DoesNotLockInToTwoCompetingAnimations) {
-  // Don't test when the event stream cannot indicate two separate content
-  // animations under the current test parameters.
-  if (GetParam().content_period < 2 * GetParam().vsync_interval)
-    return;
-
-  // Start the first animation and run for a bit, and expect the sampler to
-  // lock-in.
-  base::TimeTicks begin = InitialTestTimeTicks();
-  base::TimeTicks end = begin + base::TimeDelta::FromSeconds(5);
-  RunEventSequence(GenerateEventSequence(begin, end, true, false),
-                   false,
-                   true,
-                   false);
-  begin = end;
-
-  // Now, keep the first animation and blend in an second animation of the same
-  // size and frame rate, but at a different position.  This will should cause
-  // the sampler to enter an "undetected" state since it's unclear which
-  // animation should be locked into.
-  end = begin + base::TimeDelta::FromSeconds(20);
-  std::vector<Event> first_animation_events =
-      GenerateEventSequence(begin, end, true, false);
-  gfx::Rect second_animation_rect(
-      gfx::Point(0, GetContentDamageRect().height()),
-      GetContentDamageRect().size());
-  std::vector<Event> both_animations_events;
-  base::TimeDelta second_animation_offset = GetParam().vsync_interval;
-  for (std::vector<Event>::const_iterator i = first_animation_events.begin();
-       i != first_animation_events.end(); ++i) {
-    both_animations_events.push_back(*i);
-    both_animations_events.push_back(
-        Event(second_animation_rect, i->second + second_animation_offset));
-  }
-  RunEventSequence(both_animations_events, true, false, false);
-  begin = end;
-
-  // Now, run just the first animation, and expect the sampler to lock-in once
-  // again.
-  end = begin + base::TimeDelta::FromSeconds(5);
-  RunEventSequence(GenerateEventSequence(begin, end, true, false),
-                   false,
-                   true,
-                   false);
-  begin = end;
-
-  // Now, blend in the second animation again, but it has half the frame rate of
-  // the first animation and damage Rects with twice the area.  This will should
-  // cause the sampler to enter an "undetected" state again.  This tests that
-  // pixel-weighting is being accounted for in the sampler's logic.
-  end = begin + base::TimeDelta::FromSeconds(20);
-  first_animation_events = GenerateEventSequence(begin, end, true, false);
-  second_animation_rect.set_width(second_animation_rect.width() * 2);
-  both_animations_events.clear();
-  bool include_second_animation_frame = true;
-  for (std::vector<Event>::const_iterator i = first_animation_events.begin();
-       i != first_animation_events.end(); ++i) {
-    both_animations_events.push_back(*i);
-    if (include_second_animation_frame) {
-      both_animations_events.push_back(
-          Event(second_animation_rect, i->second + second_animation_offset));
-    }
-    include_second_animation_frame = !include_second_animation_frame;
-  }
-  RunEventSequence(both_animations_events, true, false, false);
-  begin = end;
-}
-
-// Tests that the frame timestamps are smooth; meaning, that when run through a
-// simulated compositor, each frame is held displayed for the right number of
-// v-sync intervals.
-TEST_P(AnimatedContentSamplerParameterizedTest, FrameTimestampsAreSmooth) {
-  // Generate 30 seconds of animated content events, run the events through
-  // AnimatedContentSampler, and record all frame timestamps being proposed
-  // once lock-in is continuous.
-  base::TimeTicks begin = InitialTestTimeTicks();
-  std::vector<Event> events = GenerateEventSequence(
-      begin,
-      begin + base::TimeDelta::FromSeconds(20),
-      true,
-      false);
-  typedef std::vector<base::TimeTicks> Timestamps;
-  Timestamps frame_timestamps;
-  for (std::vector<Event>::const_iterator i = events.begin(); i != events.end();
-       ++i) {
-    sampler()->ConsiderPresentationEvent(i->first, i->second);
-    if (sampler()->HasProposal()) {
-      if (sampler()->ShouldSample()) {
-        frame_timestamps.push_back(sampler()->frame_timestamp());
-        sampler()->RecordSample(sampler()->frame_timestamp());
-      }
-    } else {
-      frame_timestamps.clear();  // Reset until continuous lock-in.
-    }
-  }
-  ASSERT_LE(2u, frame_timestamps.size());
-
-  // Iterate through the |frame_timestamps|, building a histogram counting the
-  // number of times each frame was displayed k times.  For example, 10 frames
-  // of 30 Hz content on a 60 Hz v-sync interval should result in
-  // display_counts[2] == 10.  Quit early if any one frame was obviously
-  // repeated too many times.
-  const int64 max_expected_repeats_per_frame = 1 +
-      std::max(GetParam().min_capture_period, GetParam().content_period) /
-          GetParam().vsync_interval;
-  std::vector<size_t> display_counts(max_expected_repeats_per_frame + 1, 0);
-  base::TimeTicks last_present_time = frame_timestamps.front();
-  for (Timestamps::const_iterator i = frame_timestamps.begin() + 1;
-       i != frame_timestamps.end(); ++i) {
-    const size_t num_vsync_intervals = static_cast<size_t>(
-        (*i - last_present_time) / GetParam().vsync_interval);
-    ASSERT_LT(0u, num_vsync_intervals);
-    ASSERT_GT(display_counts.size(), num_vsync_intervals);  // Quit early.
-    ++display_counts[num_vsync_intervals];
-    last_present_time += num_vsync_intervals * GetParam().vsync_interval;
-  }
-
-  // Analyze the histogram for an expected result pattern.  If the frame
-  // timestamps are smooth, there should only be one or two buckets with
-  // non-zero counts and they should be next to each other.  Because the clock
-  // precision for the event_times provided to the sampler is very granular
-  // (i.e., the vsync_interval), it's okay if other buckets have a tiny "stray"
-  // count in this test.
-  size_t highest_count = 0;
-  size_t second_highest_count = 0;
-  for (size_t repeats = 1; repeats < display_counts.size(); ++repeats) {
-    DVLOG(1) << "display_counts[" << repeats << "] is "
-             << display_counts[repeats];
-    if (display_counts[repeats] >= highest_count) {
-      second_highest_count = highest_count;
-      highest_count = display_counts[repeats];
-    } else if (display_counts[repeats] > second_highest_count) {
-      second_highest_count = display_counts[repeats];
-    }
-  }
-  size_t stray_count_remaining =
-      (frame_timestamps.size() - 1) - (highest_count + second_highest_count);
-  // Expect no more than 0.75% of frames fall outside the two main buckets.
-  EXPECT_GT(frame_timestamps.size() * 75 / 10000, stray_count_remaining);
-  for (size_t repeats = 1; repeats < display_counts.size() - 1; ++repeats) {
-    if (display_counts[repeats] == highest_count) {
-      EXPECT_EQ(second_highest_count, display_counts[repeats + 1]);
-      ++repeats;
-    } else if (display_counts[repeats] == second_highest_count) {
-      EXPECT_EQ(highest_count, display_counts[repeats + 1]);
-      ++repeats;
-    } else {
-      EXPECT_GE(stray_count_remaining, display_counts[repeats]);
-      stray_count_remaining -= display_counts[repeats];
-    }
-  }
-}
-
-// Tests that frame timestamps are "lightly pushed" back towards the original
-// presentation event times, which tells us the AnimatedContentSampler can
-// account for sources of timestamp drift and correct the drift.
-TEST_P(AnimatedContentSamplerParameterizedTest,
-       FrameTimestampsConvergeTowardsEventTimes) {
-  const int max_drift_increment_millis = 3;
-
-  // Generate a full minute of events.
-  const base::TimeTicks begin = InitialTestTimeTicks();
-  const base::TimeTicks end = begin + base::TimeDelta::FromMinutes(1);
-  std::vector<Event> events = GenerateEventSequence(begin, end, true, false);
-
-  // Modify the event sequence so that 1-3 ms of additional drift is suddenly
-  // present every 100 events.  This is meant to simulate that, external to
-  // AnimatedContentSampler, the video hardware vsync timebase is being
-  // refreshed and is showing severe drift from the system clock.
-  base::TimeDelta accumulated_drift;
-  for (size_t i = 1; i < events.size(); ++i) {
-    if (i % 100 == 0) {
-      accumulated_drift += base::TimeDelta::FromMilliseconds(
-          GetRandomInRange(1, max_drift_increment_millis + 1));
-    }
-    events[i].second += accumulated_drift;
-  }
-
-  // Run all the events through the sampler and track the last rewritten frame
-  // timestamp.
-  base::TimeTicks last_frame_timestamp;
-  for (std::vector<Event>::const_iterator i = events.begin(); i != events.end();
-       ++i) {
-    sampler()->ConsiderPresentationEvent(i->first, i->second);
-    if (sampler()->ShouldSample())
-      last_frame_timestamp = sampler()->frame_timestamp();
-  }
-
-  // If drift was accounted for, the |last_frame_timestamp| should be close to
-  // the last event's timestamp.
-  const base::TimeDelta total_error =
-      events.back().second - last_frame_timestamp;
-  const base::TimeDelta max_acceptable_error = GetParam().min_capture_period +
-      base::TimeDelta::FromMilliseconds(max_drift_increment_millis);
-  EXPECT_NEAR(0.0,
-              total_error.InMicroseconds(),
-              max_acceptable_error.InMicroseconds());
-}
-
-INSTANTIATE_TEST_CASE_P(
-    ,
-    AnimatedContentSamplerParameterizedTest,
-    ::testing::Values(
-         // Typical frame rate content: Compositor runs at 60 Hz, capture at 30
-         // Hz, and content video animates at 30, 25, or 24 Hz.
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(30)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(25)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(24)),
-
-         // High frame rate content that leverages the Compositor's
-         // capabilities, but capture is still at 30 Hz.
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(60)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(50)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(48)),
-
-         // High frame rate content that leverages the Compositor's
-         // capabilities, and capture is also a buttery 60 Hz.
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(60), FpsAsPeriod(60)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(60), FpsAsPeriod(50)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(60), FpsAsPeriod(48)),
-
-         // On some platforms, the Compositor runs at 50 Hz.
-         Scenario(FpsAsPeriod(50), FpsAsPeriod(30), FpsAsPeriod(30)),
-         Scenario(FpsAsPeriod(50), FpsAsPeriod(30), FpsAsPeriod(25)),
-         Scenario(FpsAsPeriod(50), FpsAsPeriod(30), FpsAsPeriod(24)),
-         Scenario(FpsAsPeriod(50), FpsAsPeriod(30), FpsAsPeriod(50)),
-         Scenario(FpsAsPeriod(50), FpsAsPeriod(30), FpsAsPeriod(48)),
-
-         // Stable, but non-standard content frame rates.
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(16)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(20)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(23)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(26)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(27)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(28)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(29)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(31)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(32)),
-         Scenario(FpsAsPeriod(60), FpsAsPeriod(30), FpsAsPeriod(33))));
-
-// Tests that VideoCaptureOracle filters out events whose timestamps are
-// decreasing.
-TEST(VideoCaptureOracleTest, EnforcesEventTimeMonotonicity) {
-  const base::TimeDelta min_capture_period =
-      base::TimeDelta::FromSeconds(1) / 30;
-  const gfx::Rect damage_rect(0, 0, 1280, 720);
-  const base::TimeDelta event_increment = min_capture_period * 2;
-
-  VideoCaptureOracle oracle(min_capture_period);
-
-  base::TimeTicks t = InitialTestTimeTicks();
-  for (int i = 0; i < 10; ++i) {
-    t += event_increment;
-    ASSERT_TRUE(oracle.ObserveEventAndDecideCapture(
-        VideoCaptureOracle::kCompositorUpdate,
-        damage_rect, t));
-  }
-
-  base::TimeTicks furthest_event_time = t;
-  for (int i = 0; i < 10; ++i) {
-    t -= event_increment;
-    ASSERT_FALSE(oracle.ObserveEventAndDecideCapture(
-        VideoCaptureOracle::kCompositorUpdate,
-        damage_rect, t));
-  }
-
-  t = furthest_event_time;
-  for (int i = 0; i < 10; ++i) {
-    t += event_increment;
-    ASSERT_TRUE(oracle.ObserveEventAndDecideCapture(
-        VideoCaptureOracle::kCompositorUpdate,
-        damage_rect, t));
-  }
-}
-
-// Tests that VideoCaptureOracle is enforcing the requirement that captured
-// frames are delivered in order.  Otherwise, downstream consumers could be
-// tripped-up by out-of-order frames or frame timestamps.
-TEST(VideoCaptureOracleTest, EnforcesFramesDeliveredInOrder) {
-  const base::TimeDelta min_capture_period =
-      base::TimeDelta::FromSeconds(1) / 30;
-  const gfx::Rect damage_rect(0, 0, 1280, 720);
-  const base::TimeDelta event_increment = min_capture_period * 2;
-
-  VideoCaptureOracle oracle(min_capture_period);
-
-  // Most basic scenario: Frames delivered one at a time, with no additional
-  // captures in-between deliveries.
-  base::TimeTicks t = InitialTestTimeTicks();
-  int last_frame_number;
-  base::TimeTicks ignored;
-  for (int i = 0; i < 10; ++i) {
-    t += event_increment;
-    ASSERT_TRUE(oracle.ObserveEventAndDecideCapture(
-        VideoCaptureOracle::kCompositorUpdate,
-        damage_rect, t));
-    last_frame_number = oracle.RecordCapture();
-    ASSERT_TRUE(oracle.CompleteCapture(last_frame_number, &ignored));
-  }
-
-  // Basic pipelined scenario: More than one frame in-flight at delivery points.
-  for (int i = 0; i < 50; ++i) {
-    const int num_in_flight = 1 + i % 3;
-    for (int j = 0; j < num_in_flight; ++j) {
-      t += event_increment;
-      ASSERT_TRUE(oracle.ObserveEventAndDecideCapture(
-          VideoCaptureOracle::kCompositorUpdate,
-          damage_rect, t));
-      last_frame_number = oracle.RecordCapture();
-    }
-    for (int j = num_in_flight - 1; j >= 0; --j) {
-      ASSERT_TRUE(oracle.CompleteCapture(last_frame_number - j, &ignored));
-    }
-  }
-
-  // Pipelined scenario with out-of-order delivery attempts rejected.
-  for (int i = 0; i < 50; ++i) {
-    const int num_in_flight = 1 + i % 3;
-    for (int j = 0; j < num_in_flight; ++j) {
-      t += event_increment;
-      ASSERT_TRUE(oracle.ObserveEventAndDecideCapture(
-          VideoCaptureOracle::kCompositorUpdate,
-          damage_rect, t));
-      last_frame_number = oracle.RecordCapture();
-    }
-    ASSERT_TRUE(oracle.CompleteCapture(last_frame_number, &ignored));
-    for (int j = 1; j < num_in_flight; ++j) {
-      ASSERT_FALSE(oracle.CompleteCapture(last_frame_number - j, &ignored));
-    }
-  }
-}
-
-// Tests that VideoCaptureOracle transitions between using its two samplers in a
-// way that does not introduce severe jank, pauses, etc.
-TEST(VideoCaptureOracleTest, TransitionsSmoothlyBetweenSamplers) {
-  const base::TimeDelta min_capture_period =
-      base::TimeDelta::FromSeconds(1) / 30;
-  const gfx::Rect animation_damage_rect(0, 0, 1280, 720);
-  const base::TimeDelta event_increment = min_capture_period * 2;
-
-  VideoCaptureOracle oracle(min_capture_period);
-
-  // Run sequences of animation events and non-animation events through the
-  // oracle.  As the oracle transitions between each sampler, make sure the
-  // frame timestamps won't trip-up downstream consumers.
-  base::TimeTicks t = InitialTestTimeTicks();
-  base::TimeTicks last_frame_timestamp;
-  for (int i = 0; i < 1000; ++i) {
-    t += event_increment;
-
-    // For every 100 events, provide 50 that will cause the
-    // AnimatedContentSampler to lock-in, followed by 50 that will cause it to
-    // lock-out (i.e., the oracle will use the SmoothEventSampler instead).
-    const bool provide_animated_content_event =
-        (i % 100) >= 25 && (i % 100) < 75;
-
-    // Only the few events that trigger the lock-out transition should be
-    // dropped, because the AnimatedContentSampler doesn't yet realize the
-    // animation ended.  Otherwise, the oracle should always decide to sample
-    // because one of its samplers says to.
-    const bool require_oracle_says_sample = (i % 100) < 75 || (i % 100) >= 78;
-    const bool oracle_says_sample = oracle.ObserveEventAndDecideCapture(
-        VideoCaptureOracle::kCompositorUpdate,
-        provide_animated_content_event ? animation_damage_rect : gfx::Rect(),
-        t);
-    if (require_oracle_says_sample)
-      ASSERT_TRUE(oracle_says_sample);
-    if (!oracle_says_sample)
-      continue;
-
-    const int frame_number = oracle.RecordCapture();
-
-    base::TimeTicks frame_timestamp;
-    ASSERT_TRUE(oracle.CompleteCapture(frame_number, &frame_timestamp));
-    ASSERT_FALSE(frame_timestamp.is_null());
-    if (!last_frame_timestamp.is_null()) {
-      const base::TimeDelta delta = frame_timestamp - last_frame_timestamp;
-      EXPECT_LE(event_increment.InMicroseconds(), delta.InMicroseconds());
-      // Right after the AnimatedContentSampler lock-out transition, there were
-      // a few frames dropped, so allow a gap in the timestamps.  Otherwise, the
-      // delta between frame timestamps should never be more than 2X the
-      // |event_increment|.
-      const base::TimeDelta max_acceptable_delta = (i % 100) == 78 ?
-          event_increment * 5 : event_increment * 2;
-      EXPECT_GE(max_acceptable_delta.InMicroseconds(), delta.InMicroseconds());
-    }
-    last_frame_timestamp = frame_timestamp;
-  }
-}
-
 }  // namespace content