Convert //cc from scoped_ptr to std::unique_ptr.

cc/scheduler/scheduler_state_machine.cc

Index: cc/scheduler/scheduler_state_machine.cc
diff --git a/cc/scheduler/scheduler_state_machine.cc b/cc/scheduler/scheduler_state_machine.cc
index 266f8870b563d42be5cee7a772b627bddbfd7954..35e73f696961f5a04d11f72962a04434aec89bcf 100644
--- a/cc/scheduler/scheduler_state_machine.cc
+++ b/cc/scheduler/scheduler_state_machine.cc
@@ -189,9 +189,9 @@ const char* SchedulerStateMachine::ActionToString(Action action) {
   return "???";
 }
 
-scoped_ptr<base::trace_event::ConvertableToTraceFormat>
+std::unique_ptr<base::trace_event::ConvertableToTraceFormat>
 SchedulerStateMachine::AsValue() const {
-  scoped_ptr<base::trace_event::TracedValue> state(
+  std::unique_ptr<base::trace_event::TracedValue> state(
       new base::trace_event::TracedValue());
   AsValueInto(state.get());
   return std::move(state);