Deprecte LoweringBuilder in favor of Reducer.

src/compiler/pipeline.cc

Index: src/compiler/pipeline.cc
diff --git a/src/compiler/pipeline.cc b/src/compiler/pipeline.cc
index da25a91f2c9e6286ee4ba0efbaeafc71b0e52bbd..2e9ef98b657cf4d4b91bf710660c6e1324371052 100644
--- a/src/compiler/pipeline.cc
+++ b/src/compiler/pipeline.cc
@@ -211,8 +211,12 @@ Handle<Code> Pipeline::GenerateCode() {
       // Lower JSOperators where we can determine types.
       PhaseStats lowering_stats(info(), PhaseStats::CREATE_GRAPH,
                                 "typed lowering");
-      JSTypedLowering lowering(&jsgraph, &source_positions);
-      lowering.LowerAllNodes();
+      SourcePositionTable::Scope pos(&source_positions,
+                                     SourcePosition::Unknown());
+      JSTypedLowering lowering(&jsgraph);
+      GraphReducer graph_reducer(&graph);
+      graph_reducer.AddReducer(&lowering);
+      graph_reducer.ReduceGraph();
 
       VerifyAndPrintGraph(&graph, "Lowered typed");
     }
@@ -224,9 +228,13 @@ Handle<Code> Pipeline::GenerateCode() {
       // Lower any remaining generic JSOperators.
       PhaseStats lowering_stats(info(), PhaseStats::CREATE_GRAPH,
                                 "generic lowering");
+      SourcePositionTable::Scope pos(&source_positions,
+                                     SourcePosition::Unknown());
       MachineOperatorBuilder machine(zone());
-      JSGenericLowering lowering(info(), &jsgraph, &machine, &source_positions);
-      lowering.LowerAllNodes();
+      JSGenericLowering lowering(info(), &jsgraph, &machine);
+      GraphReducer graph_reducer(&graph);
+      graph_reducer.AddReducer(&lowering);
+      graph_reducer.ReduceGraph();
 
       VerifyAndPrintGraph(&graph, "Lowered generic");
     }