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

cc/scheduler/scheduler_settings.cc

Index: cc/scheduler/scheduler_settings.cc
diff --git a/cc/scheduler/scheduler_settings.cc b/cc/scheduler/scheduler_settings.cc
index 79576acc1a4238a4082528032be03d654f35d110..6f174fa1ba9c6f5a34a119bcb4332c1dce0fc10a 100644
--- a/cc/scheduler/scheduler_settings.cc
+++ b/cc/scheduler/scheduler_settings.cc
@@ -24,9 +24,9 @@ SchedulerSettings::SchedulerSettings(const SchedulerSettings& other) = default;
 
 SchedulerSettings::~SchedulerSettings() {}
 
-scoped_ptr<base::trace_event::ConvertableToTraceFormat>
+std::unique_ptr<base::trace_event::ConvertableToTraceFormat>
 SchedulerSettings::AsValue() const {
-  scoped_ptr<base::trace_event::TracedValue> state(
+  std::unique_ptr<base::trace_event::TracedValue> state(
       new base::trace_event::TracedValue());
   state->SetBoolean("use_external_begin_frame_source",
                     use_external_begin_frame_source);