Split nested namespaces declaration in two lines in accordance with C++ Style Guide.

src/arm/simulator-arm.h

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 48 matching lines @@
 
 // The simulator has its own stack. Thus it has a different stack limit from
 // the C-based native code.
 #define GENERATED_CODE_STACK_LIMIT(limit) \
   (assembler::arm::Simulator::current()->StackLimit())
 
 
 #include "constants-arm.h"
 
 
-namespace assembler { namespace arm {
+namespace assembler {
+namespace arm {
 
 class Simulator {
  public:
   friend class Debugger;
 
   enum Register {
     no_reg = -1,
     r0 = 0, r1, r2, r3, r4, r5, r6, r7,
     r8, r9, r10, r11, r12, r13, r14, r15,
     num_registers,
@@ skipping 115 matching lines @@
   // registered breakpoints
   Instr* break_pc_;
   instr_t break_instr_;
 };
 
 } }  // namespace assembler::arm
 
 #endif  // defined(__arm__)
 
 #endif  // V8_ARM_SIMULATOR_ARM_H_