Simplify scheduler API by removing zone scopes.

src/compiler/scheduler.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_SCHEDULER_H_
 #define V8_COMPILER_SCHEDULER_H_
 
 #include "src/v8.h"
 
 #include "src/compiler/opcodes.h"
 #include "src/compiler/schedule.h"
 #include "src/compiler/zone-pool.h"
 #include "src/zone-containers.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 class SpecialRPONumberer;
 
 // Computes a schedule from a graph, placing nodes into basic blocks and
 // ordering the basic blocks in the special RPO order.
 class Scheduler {
  public:
   // The complete scheduling algorithm. Creates a new schedule and places all
   // nodes from the graph into it.
-  static Schedule* ComputeSchedule(ZonePool* zone_pool, Graph* graph);
+  static Schedule* ComputeSchedule(Zone* zone, Graph* graph);
 
   // Compute the RPO of blocks in an existing schedule.
-  static BasicBlockVector* ComputeSpecialRPO(ZonePool* zone_pool,
-                                             Schedule* schedule);
+  static BasicBlockVector* ComputeSpecialRPO(Zone* zone, Schedule* schedule);
 
  private:
   // Placement of a node changes during scheduling. The placement state
   // transitions over time while the scheduler is choosing a position:
   //
   //                   +---------------------+-----+----> kFixed
   //                  /                     /     /
   //    kUnknown ----+------> kCoupled ----+     /
   //                  \                         /
   //                   +----> kSchedulable ----+--------> kScheduled
@@ skipping 62 matching lines @@
 
   void FuseFloatingControl(BasicBlock* block, Node* node);
   void MovePlannedNodes(BasicBlock* from, BasicBlock* to);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_SCHEDULER_H_