Make IdleTimeEstimator ignore nested tasks

components/scheduler/renderer/idle_time_estimator.cc

Index: components/scheduler/renderer/idle_time_estimator.cc
diff --git a/components/scheduler/renderer/idle_time_estimator.cc b/components/scheduler/renderer/idle_time_estimator.cc
index 5d572a2831776854a41a2e03cf1ac1fbb2f83943..52e72da2eba36a009b958afba2ea72cc3f80893c 100644
--- a/components/scheduler/renderer/idle_time_estimator.cc
+++ b/components/scheduler/renderer/idle_time_estimator.cc
@@ -36,7 +36,8 @@ base::TimeDelta IdleTimeEstimator::GetExpectedIdleDuration(
 void IdleTimeEstimator::DidCommitFrameToCompositor() {
   // This will run inside of a WillProcessTask / DidProcessTask pair, let
   // DidProcessTask know a frame was comitted.
-  did_commit_ = true;
+  if (nesting_level_ == 1)
+    did_commit_ = true;
 }
 
 void IdleTimeEstimator::Clear() {
@@ -54,11 +55,16 @@ void IdleTimeEstimator::SetTimeSourceForTesting(
 
 void IdleTimeEstimator::WillProcessTask(const base::PendingTask& pending_task) {
   nesting_level_++;
-  task_start_time_ = time_source_->NowTicks();
+  if (nesting_level_ == 1)
+    task_start_time_ = time_source_->NowTicks();
 }
 
 void IdleTimeEstimator::DidProcessTask(const base::PendingTask& pending_task) {
-  DCHECK_EQ(nesting_level_, 1);
+  nesting_level_--;
+  DCHECK_GE(nesting_level_, 0);
+  if (nesting_level_ != 0)
+    return;
+
   cumulative_compositor_runtime_ += time_source_->NowTicks() - task_start_time_;
 
   if (did_commit_) {
@@ -67,7 +73,6 @@ void IdleTimeEstimator::DidProcessTask(const base::PendingTask& pending_task) {
     cumulative_compositor_runtime_ = base::TimeDelta();
     did_commit_ = false;
   }
-  nesting_level_--;
 }
 
 }  // namespace scheduler