Revert 210101 "cc: Fix and simplify DelayBasedTimeSource"

cc/scheduler/delay_based_time_source_unittest.cc

Index: cc/scheduler/delay_based_time_source_unittest.cc
===================================================================
--- cc/scheduler/delay_based_time_source_unittest.cc	(revision 226578)
+++ cc/scheduler/delay_based_time_source_unittest.cc	(working copy)
@@ -88,7 +88,7 @@
       FakeDelayBasedTimeSource::Create(Interval(), task_runner.get());
   timer->SetClient(&client);
   timer->SetActive(true);
-  // Run the first tick.
+  // Run the first task, as that activates the timer and picks up a timebase.
   task_runner->RunPendingTasks();
 
   EXPECT_EQ(16, task_runner->NextPendingTaskDelay().InMilliseconds());
@@ -109,7 +109,7 @@
       FakeDelayBasedTimeSource::Create(Interval(), task_runner.get());
   timer->SetClient(&client);
   timer->SetActive(true);
-  // Run the first tick.
+  // Run the first task, as that activates the timer and picks up a timebase.
   task_runner->RunPendingTasks();
 
   EXPECT_EQ(16, task_runner->NextPendingTaskDelay().InMilliseconds());
@@ -122,7 +122,7 @@
 }
 
 // At 60Hz, when the tick returns at exactly 2*interval after the requested next
-// time, make sure a 0ms next delay is posted.
+// time, make sure a 16ms next delay is posted.
 TEST(DelayBasedTimeSource, NextDelaySaneWhenExactlyTwiceAfterRequestedTime) {
   scoped_refptr<base::TestSimpleTaskRunner> task_runner =
       new base::TestSimpleTaskRunner;
@@ -131,7 +131,7 @@
       FakeDelayBasedTimeSource::Create(Interval(), task_runner.get());
   timer->SetClient(&client);
   timer->SetActive(true);
-  // Run the first tick.
+  // Run the first task, as that activates the timer and picks up a timebase.
   task_runner->RunPendingTasks();
 
   EXPECT_EQ(16, task_runner->NextPendingTaskDelay().InMilliseconds());
@@ -139,7 +139,7 @@
   timer->SetNow(timer->Now() + 2 * Interval());
   task_runner->RunPendingTasks();
 
-  EXPECT_EQ(0, task_runner->NextPendingTaskDelay().InMilliseconds());
+  EXPECT_EQ(16, task_runner->NextPendingTaskDelay().InMilliseconds());
 }
 
 // At 60Hz, when the tick returns at 2*interval and a bit after the requested
@@ -152,7 +152,7 @@
       FakeDelayBasedTimeSource::Create(Interval(), task_runner.get());
   timer->SetClient(&client);
   timer->SetActive(true);
-  // Run the first tick.
+  // Run the first task, as that activates the timer and picks up a timebase.
   task_runner->RunPendingTasks();
 
   EXPECT_EQ(16, task_runner->NextPendingTaskDelay().InMilliseconds());
@@ -174,7 +174,7 @@
       FakeDelayBasedTimeSource::Create(Interval(), task_runner.get());
   timer->SetClient(&client);
   timer->SetActive(true);
-  // Run the first tick.
+  // Run the first task, as that activates the timer and picks up a timebase.
   task_runner->RunPendingTasks();
 
   EXPECT_EQ(16, task_runner->NextPendingTaskDelay().InMilliseconds());
@@ -196,7 +196,7 @@
       FakeDelayBasedTimeSource::Create(Interval(), task_runner.get());
   timer->SetClient(&client);
   timer->SetActive(true);
-  // Run the first tick.
+  // Run the first task, as that activates the timer and picks up a timebase.
   task_runner->RunPendingTasks();
 
   EXPECT_EQ(16, task_runner->NextPendingTaskDelay().InMilliseconds());
@@ -227,7 +227,7 @@
       FakeDelayBasedTimeSource::Create(Interval(), task_runner.get());
   timer->SetClient(&client);
   timer->SetActive(true);
-  // Run the first tick.
+  // Run the first task, as that activates the timer and picks up a timebase.
   task_runner->RunPendingTasks();
 
   EXPECT_EQ(16, task_runner->NextPendingTaskDelay().InMilliseconds());
@@ -271,7 +271,7 @@
       FakeDelayBasedTimeSource::Create(Interval(), task_runner.get());
   timer->SetClient(&client);
   timer->SetActive(true);
-  // Run the first tick.
+  // Run the first task, as that activates the timer and picks up a timebase.
   task_runner->RunPendingTasks();
 
   EXPECT_EQ(16, task_runner->NextPendingTaskDelay().InMilliseconds());