cc: Remove background ticking from LTHI.

cc/test/scheduler_test_common.cc

Index: cc/test/scheduler_test_common.cc
diff --git a/cc/test/scheduler_test_common.cc b/cc/test/scheduler_test_common.cc
index f25d6eb142452e8daf05ba9af45efe72d3bdd588..7f730debe117fdd16036c31bab0892f5f1a68395 100644
--- a/cc/test/scheduler_test_common.cc
+++ b/cc/test/scheduler_test_common.cc
@@ -98,21 +98,6 @@ TestSchedulerFrameSourcesConstructor::ConstructPrimaryFrameSource(
 }
 
 BeginFrameSource*
-TestSchedulerFrameSourcesConstructor::ConstructBackgroundFrameSource(
-    Scheduler* scheduler) {
-  TRACE_EVENT1(
-      "cc",
-      "TestSchedulerFrameSourcesConstructor::ConstructBackgroundFrameSource",
-      "source",
-      "TestSyntheticBeginFrameSource");
-  DCHECK(!(scheduler->background_frame_source_internal_));
-  scheduler->background_frame_source_internal_ =
-      TestSyntheticBeginFrameSource::Create(
-          now_src_, test_task_runner_, base::TimeDelta::FromSeconds(1));
-  return scheduler->background_frame_source_internal_.get();
-}
-
-BeginFrameSource*
 TestSchedulerFrameSourcesConstructor::ConstructUnthrottledFrameSource(
     Scheduler* scheduler) {
   TRACE_EVENT1(