Remove duplication in Scheduler and simplify interface. Make ComputeSchedule() and ComputeSpecialRP…

src/compiler/scheduler.h

Index: src/compiler/scheduler.h
diff --git a/src/compiler/scheduler.h b/src/compiler/scheduler.h
index 843b071a9832bb18320ea309e73990a9dc84b05c..dabffff53947216f60dfe9a18b3fd8d033c44383 100644
--- a/src/compiler/scheduler.h
+++ b/src/compiler/scheduler.h
@@ -18,14 +18,15 @@ namespace v8 {
 namespace internal {
 namespace compiler {
 
+// Computes a schedule from a graph, placing nodes into basic blocks and
+// ordering the basic blocks in the special RPO order.
 class Scheduler {
  public:
-  explicit Scheduler(Zone* zone);
-  Scheduler(Zone* zone, Graph* graph, Schedule* schedule);
-
-  Schedule* NewSchedule(Graph* graph);
+  // Create a new schedule and place all computations from the graph in it.
+  static Schedule* ComputeSchedule(Graph* graph);
 
-  BasicBlockVector* ComputeSpecialRPO();
+  // Compute the RPO of blocks in an existing schedule.
+  static BasicBlockVector* ComputeSpecialRPO(Schedule* schedule);
 
  private:
   Zone* zone_;
@@ -42,6 +43,8 @@ class Scheduler {
   NodeVector schedule_root_nodes_;
   IntVector schedule_early_rpo_index_;
 
+  Scheduler(Zone* zone, Graph* graph, Schedule* schedule);
+
   int GetRPONumber(BasicBlock* block) {
     DCHECK(block->rpo_number_ >= 0 &&
            block->rpo_number_ < static_cast<int>(schedule_->rpo_order_.size()));