Revert of Remove register index/code indirection

src/compiler/pipeline.h

 // 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.
 
 #ifndef V8_COMPILER_PIPELINE_H_
 #define V8_COMPILER_PIPELINE_H_
 
 // Clients of this interface shouldn't depend on lots of compiler internals.
 // Do not include anything from src/compiler here!
 #include "src/compiler.h"
 
 namespace v8 {
 namespace internal {
-
-class RegisterConfiguration;
-
 namespace compiler {
 
 class CallDescriptor;
 class Graph;
 class InstructionSequence;
 class Linkage;
 class PipelineData;
+class RegisterConfiguration;
 class Schedule;
 
 class Pipeline {
  public:
   explicit Pipeline(CompilationInfo* info) : info_(info) {}
 
   // Run the entire pipeline and generate a handle to a code object.
   Handle<Code> GenerateCode();
 
   // Run the pipeline on an interpreter bytecode handler machine graph and
@@ skipping 38 matching lines @@
   Handle<Code> ScheduleAndGenerateCode(CallDescriptor* call_descriptor);
   void AllocateRegisters(const RegisterConfiguration* config,
                          CallDescriptor* descriptor, bool run_verifier);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_PIPELINE_H_