Fix Omnibox.CharTypedToRepaintLatency regression with D3DVsync experiment

content/browser/compositor/gpu_vsync_begin_frame_source_unittest.cc

Index: content/browser/compositor/gpu_vsync_begin_frame_source_unittest.cc
diff --git a/content/browser/compositor/gpu_vsync_begin_frame_source_unittest.cc b/content/browser/compositor/gpu_vsync_begin_frame_source_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..90e9efb6c24fbc88419389b7ea8ae5304d99af53
--- /dev/null
+++ b/content/browser/compositor/gpu_vsync_begin_frame_source_unittest.cc
@@ -0,0 +1,177 @@
+// Copyright 2017 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/compositor/gpu_vsync_begin_frame_source.h"
+
+#include "base/macros.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace content {
+namespace {
+
+class TestBeginFrameObserver : public cc::BeginFrameObserverBase {
+ public:
+  TestBeginFrameObserver() {}

[sunnyps, 2017/05/30 22:13:17]

nit: Can you = default the ctors/dtors instead?

[stanisc, 2017/05/31 01:17:53]

Done.

+
+  int begin_frame_count() { return begin_frame_count_; }
+
+ private:
+  bool OnBeginFrameDerivedImpl(const cc::BeginFrameArgs& args) override {
+    begin_frame_count_++;
+    return true;
+  }
+
+  void OnBeginFrameSourcePausedChanged(bool paused) override{};

[sunnyps, 2017/05/30 22:13:17]

nit: space between override and {} in accordance with the style guide

[stanisc, 2017/05/31 01:17:53]

It is interesting that presubmit complains when this space is here and 'git cl
format' removes it. I've added it back anyway.

+
+  int begin_frame_count_ = 0;
+
+  DISALLOW_COPY_AND_ASSIGN(TestBeginFrameObserver);
+};
+
+class TestGpuVSyncBeginFrameSource : public GpuVSyncBeginFrameSource {
+ public:
+  explicit TestGpuVSyncBeginFrameSource(GpuVSyncControl* vsync_control)
+      : GpuVSyncBeginFrameSource(vsync_control) {}
+
+  void SetNow(base::TimeTicks now) { now_ = now; }
+
+ private:
+  base::TimeTicks Now() const override { return now_; }
+
+  base::TimeTicks now_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestGpuVSyncBeginFrameSource);
+};
+
+class GpuVSyncBeginFrameSourceTest : public testing::Test,
+                                     public GpuVSyncControl {
+ public:
+  GpuVSyncBeginFrameSourceTest() {}
+  ~GpuVSyncBeginFrameSourceTest() override {}
+
+  void SetUp() override {}
+  void TearDown() override {}

[sunnyps, 2017/05/30 22:13:17]

nit: Can you remove SetUp and TearDown if you're not using them?

[stanisc, 2017/05/31 01:17:53]

Done.

+
+ protected:
+  void SetNeedsVSync(bool needs_vsync) override { needs_vsync_ = needs_vsync; }
+
+  bool needs_vsync_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(GpuVSyncBeginFrameSourceTest);
+};
+
+// Test that an observer can be added to BFS and that it receives OnBeginFrame
+// notification.
+TEST_F(GpuVSyncBeginFrameSourceTest, BasicTest) {
+  TestBeginFrameObserver observer;
+  TestGpuVSyncBeginFrameSource begin_frame_source(this);
+
+  base::TimeTicks now = base::TimeTicks() + base::TimeDelta::FromHours(2);
+  begin_frame_source.SetNow(now);
+
+  EXPECT_FALSE(needs_vsync_);
+
+  begin_frame_source.AddObserver(&observer);
+
+  EXPECT_TRUE(needs_vsync_);
+  EXPECT_FALSE(observer.LastUsedBeginFrameArgs().IsValid());
+
+  base::TimeTicks frame_time = now - base::TimeDelta::FromSeconds(1);
+  base::TimeDelta interval = base::TimeDelta::FromSeconds(2);
+
+  begin_frame_source.OnVSync(frame_time, interval);
+
+  EXPECT_EQ(1, observer.begin_frame_count());
+
+  cc::BeginFrameArgs args = observer.LastUsedBeginFrameArgs();
+  EXPECT_TRUE(args.IsValid());
+  EXPECT_EQ(frame_time, args.frame_time);
+  EXPECT_EQ(interval, args.interval);
+  EXPECT_EQ(frame_time + interval, args.deadline);
+  EXPECT_EQ(cc::BeginFrameArgs::kStartingFrameNumber + 1, args.sequence_number);
+  EXPECT_EQ(cc::BeginFrameArgs::NORMAL, args.type);
+  EXPECT_EQ(begin_frame_source.source_id(), args.source_id);
+
+  // Make sure that the deadline time is correctly advanced forward to be after
+  // 'now' when frame time is way behind.
+  now += base::TimeDelta::FromSeconds(10);
+  begin_frame_source.SetNow(now);
+  // Frame time is 5 seconds behind but the deadline should be 1 second after
+  // 'now' considering the 2 second interval.
+  frame_time = now - base::TimeDelta::FromSeconds(5);
+
+  begin_frame_source.OnVSync(frame_time, interval);
+
+  EXPECT_EQ(2, observer.begin_frame_count());
+
+  args = observer.LastUsedBeginFrameArgs();
+  EXPECT_TRUE(args.IsValid());
+  EXPECT_EQ(frame_time, args.frame_time);

[sunnyps, 2017/05/30 22:13:17]

nit: Should the BFS also adjust the frame time like it adjusts the deadline?

[stanisc, 2017/05/31 01:17:53]

frame time is passed to RAF so I think it shouldn't be adjusted.

+  EXPECT_EQ(interval, args.interval);
+  EXPECT_EQ(now + base::TimeDelta::FromSeconds(1), args.deadline);
+  EXPECT_EQ(cc::BeginFrameArgs::kStartingFrameNumber + 2, args.sequence_number);
+  EXPECT_EQ(cc::BeginFrameArgs::NORMAL, args.type);
+  EXPECT_EQ(begin_frame_source.source_id(), args.source_id);
+
+  begin_frame_source.RemoveObserver(&observer);
+
+  EXPECT_EQ(2, observer.begin_frame_count());
+  EXPECT_FALSE(needs_vsync_);
+}
+
+// Test that MISSED OnBeginFrame is produced as expected.
+TEST_F(GpuVSyncBeginFrameSourceTest, MissedBeginFrameArgs) {
+  TestBeginFrameObserver observer1;
+  TestBeginFrameObserver observer2;
+  TestGpuVSyncBeginFrameSource begin_frame_source(this);
+
+  base::TimeTicks now = base::TimeTicks() + base::TimeDelta::FromHours(2);
+  begin_frame_source.SetNow(now);
+
+  begin_frame_source.AddObserver(&observer1);

[sunnyps, 2017/05/30 22:13:17]

nit: Can you add an EXPECT that the observer doesn't get a missed frame here?

[stanisc, 2017/05/31 01:17:53]

Done.

+
+  base::TimeDelta interval = base::TimeDelta::FromSeconds(2);
+
+  // Trigger first OnBeginFrame 5 seconds behind now.
+  begin_frame_source.OnVSync(now - base::TimeDelta::FromSeconds(5), interval);

[sunnyps, 2017/05/30 22:13:17]

nit: Can you add EXPECTs for the observer's begin frame?

[stanisc, 2017/05/31 01:17:53]

This is covered by BasicTest. I've added a simple check for the number of
BeginFrame received and the arg type.

+
+  // Remove the first observer and add it back. It should get a more
+  // recent missed notification calculated from the projection of the previous
+  // notification.
+  begin_frame_source.RemoveObserver(&observer1);
+  begin_frame_source.AddObserver(&observer1);
+
+  EXPECT_EQ(2, observer1.begin_frame_count());
+
+  // The projected MISSED frame_time should be 1 second behind 'now'.
+  base::TimeTicks timestamp1 = now - base::TimeDelta::FromSeconds(1);
+  cc::BeginFrameArgs args1 = observer1.LastUsedBeginFrameArgs();
+  EXPECT_TRUE(args1.IsValid());
+  EXPECT_EQ(timestamp1, args1.frame_time);

[sunnyps, 2017/05/30 22:13:17]

nit: EXPECT for the deadline?

[stanisc, 2017/05/31 01:17:53]

Done.

+  EXPECT_EQ(cc::BeginFrameArgs::kStartingFrameNumber + 2,
+            args1.sequence_number);
+  EXPECT_EQ(cc::BeginFrameArgs::MISSED, args1.type);
+
+  // Add second observer which should receive the same notification.
+  begin_frame_source.AddObserver(&observer2);
+
+  EXPECT_EQ(1, observer2.begin_frame_count());
+
+  cc::BeginFrameArgs args2 = observer2.LastUsedBeginFrameArgs();
+  EXPECT_TRUE(args2.IsValid());
+  EXPECT_EQ(timestamp1, args2.frame_time);

[sunnyps, 2017/05/30 22:13:17]

nit: deadline?

[stanisc, 2017/05/31 01:17:53]

Done.

+  EXPECT_EQ(cc::BeginFrameArgs::kStartingFrameNumber + 2,
+            args2.sequence_number);
+  EXPECT_EQ(cc::BeginFrameArgs::MISSED, args2.type);
+
+  // Adding and removing the second observer shouldn't produce any
+  // new notifications.
+  begin_frame_source.RemoveObserver(&observer2);
+  begin_frame_source.AddObserver(&observer2);
+
+  EXPECT_EQ(1, observer2.begin_frame_count());
+}
+
+}  // namespace
+}  // namespace content