cc: Adding BeginFrameTracker object and removing Now() from LTHI.

cc/scheduler/scheduler_unittest.cc

Index: cc/scheduler/scheduler_unittest.cc
diff --git a/cc/scheduler/scheduler_unittest.cc b/cc/scheduler/scheduler_unittest.cc
index 80d54d2306d093771f092d799be69feeb543c953..372f663d27fd77d476c2e41c5115c72ed66eaabc 100644
--- a/cc/scheduler/scheduler_unittest.cc
+++ b/cc/scheduler/scheduler_unittest.cc
@@ -1146,26 +1146,26 @@ TEST(SchedulerTest,
     SkipMainFrameIfHighLatencyAndCanCommitAndActivateBeforeDeadline) {
   // Set up client so that estimates indicate that we can commit and activate
   // before the deadline (~8ms by default).
-  MainFrameInHighLatencyMode(1, 1, false, false);
+  EXPECT_SCOPED(MainFrameInHighLatencyMode(1, 1, false, false));
 }
 
 TEST(SchedulerTest, NotSkipMainFrameIfHighLatencyAndCanCommitTooLong) {
   // Set up client so that estimates indicate that the commit cannot finish
   // before the deadline (~8ms by default).
-  MainFrameInHighLatencyMode(10, 1, false, true);
+  EXPECT_SCOPED(MainFrameInHighLatencyMode(10, 1, false, true));
 }
 
 TEST(SchedulerTest, NotSkipMainFrameIfHighLatencyAndCanActivateTooLong) {
   // Set up client so that estimates indicate that the activate cannot finish
   // before the deadline (~8ms by default).
-  MainFrameInHighLatencyMode(1, 10, false, true);
+  EXPECT_SCOPED(MainFrameInHighLatencyMode(1, 10, false, true));
 }
 
 TEST(SchedulerTest, NotSkipMainFrameInPreferImplLatencyMode) {
   // Set up client so that estimates indicate that we can commit and activate
   // before the deadline (~8ms by default), but also enable impl latency takes
   // priority mode.
-  MainFrameInHighLatencyMode(1, 1, true, true);
+  EXPECT_SCOPED(MainFrameInHighLatencyMode(1, 1, true, true));
 }
 
 TEST(SchedulerTest, PollForCommitCompletion) {