Fix clang build; remove dead private field.

src/compiler/scheduler.cc

 // 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.
 
 #include "src/compiler/scheduler.h"
 
 #include "src/compiler/graph.h"
 #include "src/compiler/graph-inl.h"
 #include "src/compiler/node.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/node-properties-inl.h"
 #include "src/data-flow.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 Scheduler::Scheduler(Zone* zone, Graph* graph, Schedule* schedule)
-    : zone_(zone),
-      graph_(graph),
+    : graph_(graph),
       schedule_(schedule),
       branches_(NodeVector::allocator_type(zone)),
       calls_(NodeVector::allocator_type(zone)),
       deopts_(NodeVector::allocator_type(zone)),
       returns_(NodeVector::allocator_type(zone)),
       loops_and_merges_(NodeVector::allocator_type(zone)),
       node_block_placement_(BasicBlockVector::allocator_type(zone)),
       unscheduled_uses_(IntVector::allocator_type(zone)),
       scheduled_nodes_(NodeVectorVector::allocator_type(zone)),
       schedule_root_nodes_(NodeVector::allocator_type(zone)),
@@ skipping 1009 matching lines @@
 
 #if DEBUG
   if (FLAG_trace_turbo_scheduler) PrintRPO(num_loops, loops, final_order);
   VerifySpecialRPO(num_loops, loops, final_order);
 #endif
   return final_order;
 }
 }
 }
 }  // namespace v8::internal::compiler