Simplify scheduler API by removing zone scopes.

test/cctest/compiler/test-instruction.cc

 // Copyright 2014 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.
 
 #include "src/v8.h"
 #include "test/cctest/cctest.h"
 
 #include "src/compiler/code-generator.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
@@ skipping 34 matching lines @@
   Linkage linkage;
   CommonOperatorBuilder common;
   MachineOperatorBuilder machine;
   TestInstrSeq* code;
 
   Zone* zone() { return main_zone(); }
 
   void allocCode() {
     if (schedule.rpo_order()->size() == 0) {
       // Compute the RPO order.
-      ZonePool zone_pool(isolate);
-      Scheduler::ComputeSpecialRPO(&zone_pool, &schedule);
+      Scheduler::ComputeSpecialRPO(main_zone(), &schedule);
       DCHECK(schedule.rpo_order()->size() > 0);
     }
     InstructionBlocks* instruction_blocks =
         TestInstrSeq::InstructionBlocksFor(main_zone(), &schedule);
     code = new TestInstrSeq(main_zone(), instruction_blocks);
   }
 
   Node* Int32Constant(int32_t val) {
     Node* node = graph.NewNode(common.Int32Constant(val));
     schedule.AddNode(schedule.start(), node);
@@ skipping 292 matching lines @@
           CHECK_EQ(inputs[z], m->InputAt(z));
         }
 
         for (size_t z = 0; z < k; z++) {
           CHECK_EQ(temps[z], m->TempAt(z));
         }
       }
     }
   }
 }