Fix cpplint errors in cc/(animation|input|layers|trees|test)/

cc/scheduler/scheduler_state_machine_unittest.cc

Index: cc/scheduler/scheduler_state_machine_unittest.cc
diff --git a/cc/scheduler/scheduler_state_machine_unittest.cc b/cc/scheduler/scheduler_state_machine_unittest.cc
index f15bb8f6294f92f032321304e24368a3cb494afb..93fc82f6f907ef02e27424a43e85f4e63c503325 100644
--- a/cc/scheduler/scheduler_state_machine_unittest.cc
+++ b/cc/scheduler/scheduler_state_machine_unittest.cc
@@ -21,7 +21,7 @@ const SchedulerStateMachine::CommitState all_commit_states[] = {
 // Exposes the protected state fields of the SchedulerStateMachine for testing
 class StateMachine : public SchedulerStateMachine {
  public:
-  StateMachine(const SchedulerSettings& scheduler_settings)
+  explicit StateMachine(const SchedulerSettings& scheduler_settings)
       : SchedulerStateMachine(scheduler_settings) {}
   void SetCommitState(CommitState cs) { commit_state_ = cs; }
   CommitState CommitState() const { return commit_state_; }