Refactoring the way begin frame sources inside scheduler work.

cc/scheduler/begin_frame_source_unittest.cc

+// Copyright 2011 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 <deque>
+
+#include "base/basictypes.h"
+#include "base/gtest_prod_util.h"
+#include "base/test/test_simple_task_runner.h"
+#include "cc/scheduler/begin_frame_source.h"
+#include "cc/test/begin_frame_args_test.h"
+#include "cc/test/scheduler_test_common.h"
+#include "testing/gmock/include/gmock/gmock.h"

[brianderson, 2014/09/24 06:03:06]

I don't understand gmock well enough to review this file quickly. I'll try to
look at it more tomorrow.

[mithro-old, 2014/09/24 17:14:55]

Acknowledged.

+#include "testing/gtest/include/gtest/gtest.h"
+
+#define EXPECT_USED cc::BeginFrameObserver::BeginFrameArgsStatus::USED

[Sami, 2014/09/24 11:12:53]

I think "using" declarations would be cleaner than these. You could add a few
for gmock too to get rid of the ::testing:: noise.

[mithro-old, 2014/09/24 17:14:55]

So it appears that the using statements and macros don't mix very well. 

1.      ../../cc/scheduler/begin_frame_source_unittest.cc:94:3
<Spelling=../../cc/scheduler/begin_frame_source_unittest.cc:44:29>: current
parser token 'USED'
2.      ../../cc/scheduler/begin_frame_source_unittest.cc:57:1: parsing
namespace 'cc'
3.      ../../cc/scheduler/begin_frame_source_unittest.cc:58:1: parsing
namespace
4.      ../../cc/scheduler/begin_frame_source_unittest.cc:92:54: parsing
function body 'TestBody'
5.      ../../cc/scheduler/begin_frame_source_unittest.cc:92:54: in compound
statement ('{}')
6.      ../../cc/scheduler/begin_frame_source_unittest.cc:94:3
<Spelling=../../cc/scheduler/begin_frame_source_unittest.cc:17:3>: in compound
statement ('{}')
clang: error: unable to execute command: Aborted (core dumped)
clang: error: clang frontend command failed due to signal (use -v to see
invocation)
clang version 3.6.0 (216630)

But it's gone now.

+
+#define EXPECT_DROPPED cc::BeginFrameObserver::BeginFrameArgsStatus::DROPPED
+
+#define EXPECT_BEGIN_FRAME_STATUS(status, obs, ...)                        \
+  {                                                                        \
+    switch (status) {                                                      \

[Sami, 2014/09/24 11:12:53]

Maybe it's just me but this feels a little too clever for its own good. I'm
picturing the errors from gmock when an expectation fails and wondering if
anyone can make sense out of them.

Could you at least split this into EXPECT_BEGIN_FRAME_USED and _DROPPED because
the two branches aren't sharing any code.

[mithro-old, 2014/09/24 17:14:55]

The GMOCK error output is actually very readable. It says which expectation
failed and prints out all the arguments and stuff.
Done.

+      case EXPECT_USED: {                                                  \
+        ::testing::Expectation exp =                                       \
+            EXPECT_CALL(                                                   \
+                obs,                                                       \
+                OnBeginFrame(CreateBeginFrameArgsForTesting(__VA_ARGS__))) \
+                .InSequence(obs.sequence)                                  \
+                .WillOnce(::testing::Return(status));                      \
+        BeginFrameArgs args = CreateBeginFrameArgsForTesting(__VA_ARGS__); \
+        EXPECT_CALL(obs, LastUsedBeginFrameArgs())                         \
+            .Times(::testing::AnyNumber())                                 \
+            .After(exp)                                                    \
+            .WillRepeatedly(::testing::Return(args));                      \
+      } break;                                                             \
+      case EXPECT_DROPPED: {                                               \
+        ::testing::Expectation exp =                                       \
+            EXPECT_CALL(                                                   \
+                obs,                                                       \
+                OnBeginFrame(CreateBeginFrameArgsForTesting(__VA_ARGS__))) \
+                .InSequence(obs.sequence)                                  \
+                .WillOnce(::testing::Return(status));                      \
+      } break;                                                             \
+    }                                                                      \
+  }
+
+#define EXPECT_BEGIN_FRAME(obs, ...) \
+  EXPECT_BEGIN_FRAME_STATUS(EXPECT_USED, obs, __VA_ARGS__);
+
+#define SEND_BEGIN_FRAME_STATUS(status, source, ...) \
+  EXPECT_EQ(                                         \
+      status,                                        \
+      source.TestOnBeginFrame(CreateBeginFrameArgsForTesting(__VA_ARGS__)));
+
+#define SEND_BEGIN_FRAME(source, ...) \
+  SEND_BEGIN_FRAME_STATUS(EXPECT_USED, source, __VA_ARGS__);
+
+#define P(pointer) (*pointer)

[Sami, 2014/09/24 11:12:53]

I think just using (*pointer) would be more readable. If you worry about the
parens then let's handle that inside the macro instead.

[mithro-old, 2014/09/24 17:14:55]

Done.

+
+namespace cc {
+namespace {
+
+class MockBeginFrameObserver : public BeginFrameObserver {
+ public:
+  MOCK_METHOD1(OnBeginFrame,
+               BeginFrameObserver::BeginFrameArgsStatus(const BeginFrameArgs&));
+  MOCK_METHOD1(OnMissedBeginFrame,
+               BeginFrameObserver::BeginFrameArgsStatus(const BeginFrameArgs&));
+  MOCK_CONST_METHOD0(LastUsedBeginFrameArgs, const BeginFrameArgs());
+
+  virtual void AsValueInto(base::debug::TracedValue* dict) const {
+    dict->SetString("type", "MockBeginFrameObserver");
+    dict->BeginDictionary("last_begin_frame_args");
+    LastUsedBeginFrameArgs().AsValueInto(dict);
+    dict->EndDictionary();
+  }
+
+  // A value different from the normal default returned by a BeginFrameObserver
+  // so it is easiable traced back here.
+  static const BeginFrameArgs kDefaultBeginFrameArgs;
+
+  MockBeginFrameObserver() {
+    // Set a "default" value returned by LastUsedBeginFrameArgs so that gMock
+    // doesn't fail an assert and instead returns useful information.
+    EXPECT_CALL(*this, LastUsedBeginFrameArgs())
+        .Times(::testing::AnyNumber())
+        .InSequence(sequence)
+        .WillRepeatedly(::testing::Return(kDefaultBeginFrameArgs));
+  }
+  virtual ~MockBeginFrameObserver() {}
+
+  ::testing::Sequence sequence;
+};
+
+TEST(MockBeginFrameObserverTest, ExpectOnBeginFrame) {
+  ::testing::NiceMock<MockBeginFrameObserver> obs;
+  EXPECT_BEGIN_FRAME(obs, 100, 200, 300);
+  EXPECT_BEGIN_FRAME(obs, 400, 600, 300);
+  EXPECT_BEGIN_FRAME(obs, 700, 900, 300);
+
+  EXPECT_EQ(obs.LastUsedBeginFrameArgs(),
+            MockBeginFrameObserver::kDefaultBeginFrameArgs);
+
+  obs.OnBeginFrame(CreateBeginFrameArgsForTesting(
+      100, 200, 300));  // One call to LastUsedBeginFrameArgs
+  EXPECT_EQ(obs.LastUsedBeginFrameArgs(),
+            CreateBeginFrameArgsForTesting(100, 200, 300));
+
+  obs.OnBeginFrame(CreateBeginFrameArgsForTesting(
+      400, 600, 300));  // Multiple calls to LastUsedBeginFrameArgs
+  EXPECT_EQ(obs.LastUsedBeginFrameArgs(),
+            CreateBeginFrameArgsForTesting(400, 600, 300));
+  EXPECT_EQ(obs.LastUsedBeginFrameArgs(),
+            CreateBeginFrameArgsForTesting(400, 600, 300));
+
+  obs.OnBeginFrame(CreateBeginFrameArgsForTesting(
+      700, 900, 300));  // No calls to LastUsedBeginFrameArgs
+
+  ::testing::Mock::VerifyAndClearExpectations(&obs);
+}
+
+TEST(MockBeginFrameObserverTest, ExpectOnBeginFrameStatus) {
+  ::testing::NiceMock<MockBeginFrameObserver> obs;
+  EXPECT_BEGIN_FRAME(obs, 100, 200, 300);
+  EXPECT_BEGIN_FRAME_STATUS(EXPECT_DROPPED, obs, 400, 600, 300);
+  EXPECT_BEGIN_FRAME_STATUS(EXPECT_DROPPED, obs, 450, 650, 300);
+  EXPECT_BEGIN_FRAME(obs, 700, 900, 300);
+
+  EXPECT_EQ(obs.LastUsedBeginFrameArgs(),
+            MockBeginFrameObserver::kDefaultBeginFrameArgs);
+
+  EXPECT_EQ(EXPECT_USED,
+            obs.OnBeginFrame(CreateBeginFrameArgsForTesting(100, 200, 300)));
+  EXPECT_EQ(obs.LastUsedBeginFrameArgs(),
+            CreateBeginFrameArgsForTesting(100, 200, 300));
+
+  EXPECT_EQ(EXPECT_DROPPED,
+            obs.OnBeginFrame(
+                CreateBeginFrameArgsForTesting(400, 600, 300)));  // Dropped
+  EXPECT_EQ(obs.LastUsedBeginFrameArgs(),
+            CreateBeginFrameArgsForTesting(100, 200, 300));
+
+  EXPECT_EQ(EXPECT_DROPPED,
+            obs.OnBeginFrame(
+                CreateBeginFrameArgsForTesting(450, 650, 300)));  // Dropped
+  EXPECT_EQ(obs.LastUsedBeginFrameArgs(),
+            CreateBeginFrameArgsForTesting(100, 200, 300));
+
+  EXPECT_EQ(EXPECT_USED,
+            obs.OnBeginFrame(CreateBeginFrameArgsForTesting(700, 900, 300)));
+  EXPECT_EQ(obs.LastUsedBeginFrameArgs(),
+            CreateBeginFrameArgsForTesting(700, 900, 300));
+
+  ::testing::Mock::VerifyAndClearExpectations(&obs);
+}
+
+const BeginFrameArgs MockBeginFrameObserver::kDefaultBeginFrameArgs =
+    CreateBeginFrameArgsForTesting(-1, -1, -1);
+
+// BeginFrameSource testing ----------------------------------------------
+TEST(BeginFrameSourceTest, ObserverManipulation) {
+  MockBeginFrameObserver obs;
+  MockBeginFrameObserver otherObs;
+  FakeBeginFrameSource source;
+
+  source.AddObserver(&obs);
+  EXPECT_EQ(&obs, source.GetObserver());
+
+#ifndef NDEBUG
+  // Adding an observer when an observer already exists should DCHECK fail.
+  EXPECT_DEATH({ source.AddObserver(&otherObs); }, "");
+
+  // Removing wrong observer should DCHECK fail.
+  EXPECT_DEATH({ source.RemoveObserver(&otherObs); }, "");
+
+  // Removing an observer when there is no observer should DCHECK fail.
+  EXPECT_DEATH({
+                 source.RemoveObserver(&obs);
+                 source.RemoveObserver(&obs);
+               },
+               "");
+#endif
+  source.RemoveObserver(&obs);
+
+  source.AddObserver(&otherObs);
+  EXPECT_EQ(&otherObs, source.GetObserver());
+  source.RemoveObserver(&otherObs);
+}
+
+TEST(BeginFrameSourceTest, Observer) {
+  FakeBeginFrameSource source;
+  MockBeginFrameObserver obs;
+  EXPECT_BEGIN_FRAME(obs, 100, 200, 300);
+  EXPECT_BEGIN_FRAME_STATUS(EXPECT_DROPPED, obs, 400, 600, 300);
+  EXPECT_BEGIN_FRAME_STATUS(EXPECT_DROPPED, obs, 450, 650, 300);
+  EXPECT_BEGIN_FRAME(obs, 700, 900, 300);
+
+  SEND_BEGIN_FRAME_STATUS(EXPECT_USED, source, 100, 200, 300);
+  SEND_BEGIN_FRAME_STATUS(EXPECT_DROPPED, source, 400, 600, 300);
+  SEND_BEGIN_FRAME_STATUS(EXPECT_DROPPED, source, 450, 650, 300);
+  SEND_BEGIN_FRAME_STATUS(EXPECT_USED, source, 700, 900, 300);
+}
+
+TEST(BeginFrameSourceTest, NoObserver) {
+  FakeBeginFrameSource source;
+  SEND_BEGIN_FRAME_STATUS(EXPECT_DROPPED, source, 100, 200, 300);
+}
+
+class LoopingBeginFrameObserver : public BeginFrameObserverMixIn {
+ public:
+  BeginFrameSource* source_;
+
+  virtual void AsValueInto(base::debug::TracedValue* dict) const OVERRIDE {
+    dict->SetString("type", "LoopingBeginFrameObserver");
+    dict->BeginDictionary("source");
+    source_->AsValueInto(dict);
+    dict->EndDictionary();
+  }
+
+ protected:
+  // BeginFrameObserverMixIn
+  virtual BeginFrameObserver::BeginFrameArgsStatus ProcessBeginFrameArgs(
+      const BeginFrameArgs& args) OVERRIDE {
+    return EXPECT_USED;
+  }
+};
+
+TEST(BeginFrameSourceTest, DetectAsValueIntoLoop) {
+  LoopingBeginFrameObserver obs;
+  FakeBeginFrameSource source;
+
+  obs.source_ = &source;
+  source.AddObserver(&obs);
+
+  scoped_refptr<base::debug::TracedValue> state =
+      new base::debug::TracedValue();
+  source.AsValueInto(state.get());
+}
+
+// BackToBackBeginFrameSource testing -----------------------------------------
+class TestBackToBackBeginFrameSource : public BackToBackBeginFrameSource {
+ public:
+  static scoped_ptr<TestBackToBackBeginFrameSource> Create(
+      scoped_refptr<TestNowSource> now_src,
+      base::SingleThreadTaskRunner* task_runner) {
+    return make_scoped_ptr(
+        new TestBackToBackBeginFrameSource(now_src, task_runner));
+  }
+
+ protected:
+  TestBackToBackBeginFrameSource(scoped_refptr<TestNowSource> now_src,
+                                 base::SingleThreadTaskRunner* task_runner)
+      : BackToBackBeginFrameSource(task_runner), now_src_(now_src) {}
+
+  virtual base::TimeTicks Now() OVERRIDE { return now_src_->Now(); }
+
+  scoped_refptr<TestNowSource> now_src_;
+};
+
+class BackToBackBeginFrameSourceTest : public ::testing::Test {
+ public:
+  static const int64_t kDeadline;
+  static const int64_t kInterval;
+
+  scoped_refptr<TestNowSource> now_src_;
+  scoped_refptr<OrderedSimpleTaskRunner> task_runner_;
+  scoped_ptr<TestBackToBackBeginFrameSource> source_;
+  scoped_ptr<MockBeginFrameObserver> obs_;
+
+  virtual void SetUp() OVERRIDE {
+    now_src_ = TestNowSource::Create(1000);
+    task_runner_ =
+        make_scoped_refptr(new OrderedSimpleTaskRunner(now_src_, false));
+    task_runner_->SetRunTaskLimit(1);
+    source_ =
+        TestBackToBackBeginFrameSource::Create(now_src_, task_runner_.get());
+    obs_ = make_scoped_ptr(new ::testing::StrictMock<MockBeginFrameObserver>());
+    source_->AddObserver(obs_.get());
+  }
+
+  virtual void TearDown() OVERRIDE { obs_.reset(); }
+};
+
+const int64_t BackToBackBeginFrameSourceTest::kDeadline =
+    BeginFrameArgs::DefaultInterval().ToInternalValue();
+
+const int64_t BackToBackBeginFrameSourceTest::kInterval =
+    BeginFrameArgs::DefaultInterval().ToInternalValue();
+
+TEST_F(BackToBackBeginFrameSourceTest, SetNeedsBeginFramesSendsBeginFrame) {
+  EXPECT_BEGIN_FRAME(P(obs_), 1000, 1000 + kDeadline, kInterval);
+  source_->SetNeedsBeginFrames(true);
+  EXPECT_TRUE(task_runner_->HasPendingTasks());
+  task_runner_->RunUntilIdle();
+
+  EXPECT_BEGIN_FRAME(P(obs_), 1100, 1100 + kDeadline, kInterval);
+  now_src_->AdvanceNowMicroseconds(100);
+  source_->DidFinishFrame(0);
+  task_runner_->RunUntilIdle();
+}
+
+TEST_F(BackToBackBeginFrameSourceTest,
+       DidFinishFrameThenSetNeedsBeginFramesProducesNoFrame) {
+  EXPECT_BEGIN_FRAME(P(obs_), 1000, 1000 + kDeadline, kInterval);
+  source_->SetNeedsBeginFrames(true);
+  task_runner_->RunUntilIdle();
+
+  source_->SetNeedsBeginFrames(false);
+  source_->DidFinishFrame(0);
+
+  EXPECT_FALSE(task_runner_->HasPendingTasks());
+}
+
+TEST_F(BackToBackBeginFrameSourceTest,
+       SetNeedsBeginFramesThenDidFinishFrameProducesNoFrame) {
+  EXPECT_BEGIN_FRAME(P(obs_), 1000, 1000 + kDeadline, kInterval);
+  source_->SetNeedsBeginFrames(true);
+  task_runner_->RunUntilIdle();
+
+  now_src_->AdvanceNowMicroseconds(100);
+  source_->DidFinishFrame(0);
+  source_->SetNeedsBeginFrames(false);
+
+  EXPECT_TRUE(task_runner_->HasPendingTasks());
+  task_runner_->RunUntilIdle();
+}
+
+TEST_F(BackToBackBeginFrameSourceTest,
+       DidFinishFrameThenTogglingSetNeedsBeginFramesProducesCorrectFrame) {
+  EXPECT_BEGIN_FRAME(P(obs_), 1000, 1000 + kDeadline, kInterval);
+  source_->SetNeedsBeginFrames(true);
+  task_runner_->RunUntilIdle();
+
+  now_src_->AdvanceNowMicroseconds(100);
+
+  source_->SetNeedsBeginFrames(false);
+  now_src_->AdvanceNowMicroseconds(10);
+  source_->DidFinishFrame(0);
+  now_src_->AdvanceNowMicroseconds(10);
+  source_->SetNeedsBeginFrames(false);
+  now_src_->AdvanceNowMicroseconds(10);
+  source_->SetNeedsBeginFrames(true);
+
+  EXPECT_BEGIN_FRAME(P(obs_), 1130, 1130 + kDeadline, kInterval);
+  EXPECT_TRUE(task_runner_->HasPendingTasks());
+  task_runner_->RunUntilIdle();
+}
+
+TEST_F(BackToBackBeginFrameSourceTest,
+       TogglingSetNeedsBeginFramesThenDidFinishFrameProducesCorrectFrame) {
+  EXPECT_BEGIN_FRAME(P(obs_), 1000, 1000 + kDeadline, kInterval);
+  source_->SetNeedsBeginFrames(true);
+  task_runner_->RunUntilIdle();
+
+  now_src_->AdvanceNowMicroseconds(100);
+  source_->DidFinishFrame(0);
+  now_src_->AdvanceNowMicroseconds(10);
+  source_->SetNeedsBeginFrames(false);
+  now_src_->AdvanceNowMicroseconds(10);
+  source_->SetNeedsBeginFrames(true);
+  now_src_->AdvanceNowMicroseconds(10);
+
+  EXPECT_BEGIN_FRAME(P(obs_), 1130, 1130 + kDeadline, kInterval);
+  EXPECT_TRUE(task_runner_->HasPendingTasks());
+  task_runner_->RunUntilIdle();
+}
+
+TEST_F(BackToBackBeginFrameSourceTest, DidFinishFrameNeedsBeginFrameFalse) {
+  source_->SetNeedsBeginFrames(false);
+  source_->DidFinishFrame(0);
+  EXPECT_FALSE(task_runner_->RunPendingTasks());
+}
+
+TEST_F(BackToBackBeginFrameSourceTest, DidFinishFrameRemainingFrames) {
+  EXPECT_BEGIN_FRAME(P(obs_), 1000, 1000 + kDeadline, kInterval);
+  source_->SetNeedsBeginFrames(true);
+  task_runner_->RunUntilIdle();
+
+  now_src_->AdvanceNowMicroseconds(100);
+
+  source_->DidFinishFrame(3);
+  EXPECT_FALSE(task_runner_->HasPendingTasks());
+  source_->DidFinishFrame(2);
+  EXPECT_FALSE(task_runner_->HasPendingTasks());
+  source_->DidFinishFrame(1);
+  EXPECT_FALSE(task_runner_->HasPendingTasks());
+
+  EXPECT_BEGIN_FRAME(P(obs_), 1100, 1100 + kDeadline, kInterval);
+  source_->DidFinishFrame(0);
+  EXPECT_EQ(base::TimeDelta(), task_runner_->DelayToNextTaskTime());
+  task_runner_->RunUntilIdle();
+}
+
+TEST_F(BackToBackBeginFrameSourceTest, DidFinishFrameMultipleCallsIdempotent) {
+  source_->SetNeedsBeginFrames(true);
+  EXPECT_BEGIN_FRAME(P(obs_), 1000, 1000 + kDeadline, kInterval);
+  task_runner_->RunUntilIdle();
+
+  now_src_->AdvanceNowMicroseconds(100);
+  source_->DidFinishFrame(0);
+  source_->DidFinishFrame(0);
+  source_->DidFinishFrame(0);
+  EXPECT_BEGIN_FRAME(P(obs_), 1100, 1100 + kDeadline, kInterval);
+  task_runner_->RunUntilIdle();
+
+  now_src_->AdvanceNowMicroseconds(100);
+  source_->DidFinishFrame(0);
+  source_->DidFinishFrame(0);
+  source_->DidFinishFrame(0);
+  EXPECT_BEGIN_FRAME(P(obs_), 1200, 1200 + kDeadline, kInterval);
+  task_runner_->RunUntilIdle();
+}
+
+TEST_F(BackToBackBeginFrameSourceTest, DelayInPostedTaskProducesCorrectFrame) {
+  EXPECT_BEGIN_FRAME(P(obs_), 1000, 1000 + kDeadline, kInterval);
+  source_->SetNeedsBeginFrames(true);
+  task_runner_->RunUntilIdle();
+
+  now_src_->AdvanceNowMicroseconds(100);
+  source_->DidFinishFrame(0);
+  now_src_->AdvanceNowMicroseconds(50);
+  EXPECT_BEGIN_FRAME(P(obs_), 1150, 1150 + kDeadline, kInterval);
+
+  EXPECT_TRUE(task_runner_->HasPendingTasks());
+  task_runner_->RunUntilIdle();
+}
+
+// SyntheticBeginFrameSource testing ------------------------------------------
+class SyntheticBeginFrameSourceTest : public ::testing::Test {
+ public:
+  scoped_refptr<TestNowSource> now_src_;
+  scoped_refptr<OrderedSimpleTaskRunner> task_runner_;
+  scoped_ptr<TestSyntheticBeginFrameSource> source_;
+  scoped_ptr<MockBeginFrameObserver> obs_;
+
+  virtual void SetUp() OVERRIDE {
+    now_src_ = TestNowSource::Create(1000);
+    task_runner_ =
+        make_scoped_refptr(new OrderedSimpleTaskRunner(now_src_, false));
+    source_ = TestSyntheticBeginFrameSource::Create(
+        now_src_, task_runner_.get(), base::TimeDelta::FromMicroseconds(10000));
+    obs_ = make_scoped_ptr(new MockBeginFrameObserver());
+    source_->AddObserver(obs_.get());
+  }
+
+  virtual void TearDown() OVERRIDE { obs_.reset(); }
+};
+
+TEST_F(SyntheticBeginFrameSourceTest,
+       SetNeedsBeginFramesCallsOnBeginFrameWithMissedTick) {
+  now_src_->SetNowMicroseconds(10010);
+  EXPECT_BEGIN_FRAME(P(obs_), 10000, 20000, 10000);
+  source_->SetNeedsBeginFrames(true);  // Should cause the last tick to be sent
+  // No tasks should need to be run for this to occur.
+}
+
+TEST_F(SyntheticBeginFrameSourceTest,
+       SetNeedsBeginFramesCallsCausesOnBeginFrame) {
+  source_->SetNeedsBeginFrames(true);
+  EXPECT_EQ(10000, task_runner_->NextTaskTime().ToInternalValue());
+
+  EXPECT_BEGIN_FRAME(P(obs_), 10000, 20000, 10000);
+  now_src_->SetNowMicroseconds(10010);
+  task_runner_->RunPendingTasks();
+}
+
+TEST_F(SyntheticBeginFrameSourceTest, BasicOperation) {
+  task_runner_->SetAutoAdvanceNowToPendingTasks(true);
+
+  source_->SetNeedsBeginFrames(true);
+  EXPECT_BEGIN_FRAME(P(obs_), 10000, 20000, 10000);
+  EXPECT_BEGIN_FRAME(P(obs_), 20000, 30000, 10000);
+  EXPECT_BEGIN_FRAME(P(obs_), 30000, 40000, 10000);
+  task_runner_->RunUntilTime(base::TimeTicks::FromInternalValue(30001));
+
+  source_->SetNeedsBeginFrames(false);
+  // No new frames....
+  task_runner_->RunUntilTime(base::TimeTicks::FromInternalValue(60000));
+}
+
+TEST_F(SyntheticBeginFrameSourceTest, VSyncChanges) {
+  task_runner_->SetAutoAdvanceNowToPendingTasks(true);
+  source_->SetNeedsBeginFrames(true);
+
+  EXPECT_BEGIN_FRAME(P(obs_), 10000, 20000, 10000);
+  EXPECT_BEGIN_FRAME(P(obs_), 20000, 30000, 10000);
+  EXPECT_BEGIN_FRAME(P(obs_), 30000, 40000, 10000);
+  task_runner_->RunUntilTime(base::TimeTicks::FromInternalValue(30001));
+
+  // Update the vsync information
+  source_->OnUpdateVSyncParameters(base::TimeTicks::FromInternalValue(27500),
+                                   base::TimeDelta::FromMicroseconds(10001));
+
+  EXPECT_BEGIN_FRAME(P(obs_), 40000, 47502, 10001);
+  EXPECT_BEGIN_FRAME(P(obs_), 47502, 57503, 10001);
+  EXPECT_BEGIN_FRAME(P(obs_), 57503, 67504, 10001);
+  task_runner_->RunUntilTime(base::TimeTicks::FromInternalValue(60000));
+}
+
+// BeginFrameSourceMultiplexer testing -----------------------------------
+class BeginFrameSourceMultiplexerTest : public ::testing::Test {
+ protected:
+  virtual void SetUp() OVERRIDE {
+    mux_ = BeginFrameSourceMultiplexer::Create();
+
+    source1_store_ = make_scoped_ptr(new FakeBeginFrameSource());
+    source2_store_ = make_scoped_ptr(new FakeBeginFrameSource());
+    source3_store_ = make_scoped_ptr(new FakeBeginFrameSource());
+
+    source1_ = source1_store_.get();
+    source2_ = source2_store_.get();
+    source3_ = source3_store_.get();
+  }
+
+  virtual void TearDown() OVERRIDE {
+    // Make sure the mux is torn down before the sources.
+    mux_.reset();
+  }
+
+  scoped_ptr<BeginFrameSourceMultiplexer> mux_;
+  FakeBeginFrameSource* source1_;
+  FakeBeginFrameSource* source2_;
+  FakeBeginFrameSource* source3_;
+
+ private:
+  scoped_ptr<FakeBeginFrameSource> source1_store_;
+  scoped_ptr<FakeBeginFrameSource> source2_store_;
+  scoped_ptr<FakeBeginFrameSource> source3_store_;
+};
+
+TEST_F(BeginFrameSourceMultiplexerTest, SourcesManipulation) {
+  EXPECT_EQ(NULL, mux_->ActiveSource());
+
+  mux_->AddSource(source1_);
+  EXPECT_EQ(source1_, mux_->ActiveSource());
+
+  mux_->SetActiveSource(NULL);
+  EXPECT_EQ(NULL, mux_->ActiveSource());
+
+  mux_->SetActiveSource(source1_);
+
+#ifndef NDEBUG
+  // Setting a source which isn't in the mux as active should DCHECK fail.
+  EXPECT_DEATH({ mux_->SetActiveSource(source2_); }, "");
+
+  // Adding a source which is already added should DCHECK fail.
+  EXPECT_DEATH({ mux_->AddSource(source1_); }, "");
+
+  // Removing a source which isn't in the mux should DCHECK fail.
+  EXPECT_DEATH({ mux_->RemoveSource(source2_); }, "");
+
+  // Removing the active source fails
+  EXPECT_DEATH({ mux_->RemoveSource(source1_); }, "");
+#endif
+
+  // Test manipulation doesn't segfault.
+  mux_->AddSource(source2_);
+  mux_->RemoveSource(source2_);
+
+  mux_->AddSource(source2_);
+  mux_->SetActiveSource(source2_);
+  EXPECT_EQ(source2_, mux_->ActiveSource());
+
+  mux_->RemoveSource(source1_);
+}
+
+TEST_F(BeginFrameSourceMultiplexerTest, NeedsBeginFrames) {
+  mux_->AddSource(source1_);
+  mux_->AddSource(source2_);
+  mux_->SetActiveSource(source1_);
+  EXPECT_EQ(source1_->needs_begin_frames_, false);
+  EXPECT_EQ(source2_->needs_begin_frames_, false);
+
+  // Check SetNeedsFrames works
+  mux_->SetNeedsBeginFrames(true);
+  EXPECT_EQ(source1_->needs_begin_frames_, true);
+  EXPECT_EQ(source2_->needs_begin_frames_, false);
+
+  mux_->SetNeedsBeginFrames(false);
+  EXPECT_EQ(source1_->needs_begin_frames_, false);
+  EXPECT_EQ(source2_->needs_begin_frames_, false);
+
+  // Checking that switching the source makes SetNeedsFrames on the
+  // subsources correctly.
+  mux_->SetNeedsBeginFrames(true);
+
+  mux_->SetActiveSource(source1_);
+  EXPECT_EQ(source1_->needs_begin_frames_, true);
+  EXPECT_EQ(source2_->needs_begin_frames_, false);
+
+  mux_->SetActiveSource(source2_);
+  EXPECT_EQ(source1_->needs_begin_frames_, false);
+  EXPECT_EQ(source2_->needs_begin_frames_, true);
+}
+
+TEST_F(BeginFrameSourceMultiplexerTest, BeginFramesSimple) {
+  mux_->AddSource(source1_);
+  mux_->AddSource(source2_);
+  mux_->SetActiveSource(source1_);
+
+  MockBeginFrameObserver obs;
+  mux_->AddObserver(&obs);
+  EXPECT_BEGIN_FRAME(obs, 100, 200, 300);
+  EXPECT_BEGIN_FRAME(obs, 400, 600, 300);
+
+  mux_->SetActiveSource(source1_);
+
+  SEND_BEGIN_FRAME(P(source1_), 100, 200, 300);
+  SEND_BEGIN_FRAME_STATUS(EXPECT_DROPPED, P(source2_), 200, 500, 300);
+
+  mux_->SetActiveSource(source2_);
+  SEND_BEGIN_FRAME(P(source2_), 400, 600, 300);
+  SEND_BEGIN_FRAME_STATUS(EXPECT_DROPPED, P(source1_), 500, 700, 300);
+}
+
+TEST_F(BeginFrameSourceMultiplexerTest, BeginFramesBackwardsProtection) {
+  mux_->AddSource(source1_);
+  mux_->AddSource(source2_);
+
+  MockBeginFrameObserver obs;
+  mux_->AddObserver(&obs);
+  EXPECT_BEGIN_FRAME(obs, 400, 600, 300);
+  EXPECT_BEGIN_FRAME(obs, 700, 900, 300);
+  EXPECT_BEGIN_FRAME(obs, 1000, 1200, 300);
+  EXPECT_BEGIN_FRAME(obs, 1001, 1201, 301);
+
+  mux_->SetActiveSource(source1_);
+  SEND_BEGIN_FRAME(P(source1_), 400, 600, 300);
+  SEND_BEGIN_FRAME(P(source1_), 700, 900, 300);
+
+  mux_->SetActiveSource(source2_);
+  SEND_BEGIN_FRAME_STATUS(EXPECT_DROPPED, P(source2_), 699, 899, 300);
+  SEND_BEGIN_FRAME(P(source2_), 1000, 1200, 300);
+
+  mux_->SetActiveSource(source1_);
+  SEND_BEGIN_FRAME(P(source1_), 1001, 1201, 301);
+}
+
+TEST_F(BeginFrameSourceMultiplexerTest, MinimumIntervalNegativeFails) {
+#ifndef NDEBUG
+  EXPECT_DEATH(
+      { mux_->SetMinimumInterval(base::TimeDelta::FromInternalValue(-100)); },
+      "");
+#endif
+}
+
+TEST_F(BeginFrameSourceMultiplexerTest, MinimumIntervalZero) {
+  mux_->SetMinimumInterval(base::TimeDelta());
+  mux_->AddSource(source1_);
+
+  MockBeginFrameObserver obs;
+  mux_->AddObserver(&obs);
+  EXPECT_BEGIN_FRAME(obs, 100, 200, 300);
+  EXPECT_BEGIN_FRAME(obs, 400, 600, 300);
+  EXPECT_BEGIN_FRAME(obs, 700, 900, 300);
+
+  SEND_BEGIN_FRAME(P(source1_), 100, 200, 300);
+  SEND_BEGIN_FRAME(P(source1_), 400, 600, 300);
+  SEND_BEGIN_FRAME(P(source1_), 700, 900, 300);
+}
+
+TEST_F(BeginFrameSourceMultiplexerTest, MinimumIntervalBasic) {
+  mux_->SetMinimumInterval(base::TimeDelta::FromInternalValue(600));
+  mux_->AddSource(source1_);
+
+  MockBeginFrameObserver obs;
+  mux_->AddObserver(&obs);
+  EXPECT_BEGIN_FRAME(obs, 100, 200, 300);
+  EXPECT_BEGIN_FRAME(obs, 700, 900, 300);
+
+  SEND_BEGIN_FRAME(P(source1_), 100, 200, 300);
+  SEND_BEGIN_FRAME_STATUS(EXPECT_DROPPED, P(source1_), 400, 600, 300);
+  SEND_BEGIN_FRAME(P(source1_), 700, 900, 300);
+}
+
+TEST_F(BeginFrameSourceMultiplexerTest, MinimumIntervalWithMultipleSources) {
+  mux_->SetMinimumInterval(base::TimeDelta::FromMicroseconds(150));
+  mux_->AddSource(source1_);
+  mux_->AddSource(source2_);
+
+  MockBeginFrameObserver obs;
+  mux_->AddObserver(&obs);
+  EXPECT_BEGIN_FRAME(obs, 400, 600, 300);
+  EXPECT_BEGIN_FRAME(obs, 700, 900, 300);
+  EXPECT_BEGIN_FRAME(obs, 1050, 1250, 300);
+
+  mux_->SetActiveSource(source1_);
+  SEND_BEGIN_FRAME(P(source1_), 400, 600, 300);
+  SEND_BEGIN_FRAME(P(source1_), 700, 900, 300);
+
+  mux_->SetActiveSource(source2_);
+  SEND_BEGIN_FRAME_STATUS(EXPECT_DROPPED, P(source2_), 750, 1050, 300);
+  SEND_BEGIN_FRAME(P(source2_), 1050, 1250, 300);
+
+  mux_->SetActiveSource(source1_);
+  SEND_BEGIN_FRAME_STATUS(EXPECT_DROPPED, P(source2_), 1100, 1400, 300);
+}
+
+}  // namespace
+}  // namespace cc