Remove unnecessary friend decls; fix Win-Clang builds

src/register-configuration.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/register-configuration.h"
 #include "src/globals.h"
 #include "src/macro-assembler.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 64 matching lines @@
             GetAllocatableAliasedDoubleRegisterCount(),
 #endif
             GetAllocatableGeneralCodes(), GetAllocatableDoubleCodes(),
             kGeneralRegisterNames, kDoubleRegisterNames) {
   }
 
   const char* general_register_name_table_[Register::kNumRegisters];
   const char* double_register_name_table_[DoubleRegister::kMaxNumRegisters];
 
  private:
-  friend struct Register;
-  friend struct DoubleRegister;
-
   static const int* GetAllocatableGeneralCodes() {
 #define REGISTER_CODE(R) Register::kCode_##R,
     static const int general_codes[] = {
         ALLOCATABLE_GENERAL_REGISTERS(REGISTER_CODE)};
 #undef REGISTER_CODE
     return general_codes;
   }
 
   static const int* GetAllocatableDoubleCodes() {
 #define REGISTER_CODE(R) DoubleRegister::kCode_##R,
@@ skipping 39 matching lines @@
   }
   for (int i = 0; i < num_allocatable_double_registers_; ++i) {
     allocatable_double_codes_mask_ |= (1 << allocatable_double_codes_[i]);
   }
 }
 
 #undef REGISTER_COUNT
 
 }  // namespace internal
 }  // namespace v8