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

src/cpu.h

 // Copyright 2006-2008 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 18 matching lines @@
 // the code less dependent on differences between different processor
 // architecture.
 // The classes have the same definition for all architectures. The
 // implementation for a particular architecture is put in cpu_<arch>.cc.
 // The build system then uses the implementation for the target architecture.
 //
 
 #ifndef V8_CPU_H_
 #define V8_CPU_H_
 
-namespace v8 { namespace internal {
+namespace v8 {
+namespace internal {
 
 // ----------------------------------------------------------------------------
 // CPU
 //
 // This class has static methods for the architecture specific functions. Add
 // methods here to cope with differences between the supported architectures.
 //
 // For each architecture the file cpu_<arch>.cc contains the implementation of
 // these functions.
 
 class CPU : public AllStatic {
  public:
   // Initializes the cpu architecture support. Called once at VM startup.
   static void Setup();
 
   // Flush instruction cache.
   static void FlushICache(void* start, size_t size);
 
   // Try to activate a system level debugger.
   static void DebugBreak();
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CPU_H_