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

src/codegen.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 70 matching lines @@
 #if V8_TARGET_ARCH_IA32
 #include "ia32/codegen-ia32.h"
 #elif V8_TARGET_ARCH_X64
 #include "x64/codegen-x64.h"
 #elif V8_TARGET_ARCH_ARM
 #include "arm/codegen-arm.h"
 #endif
 
 #include "register-allocator.h"
 
-namespace v8 { namespace internal {
+namespace v8 {
+namespace internal {
 
 
 // Code generation can be nested.  Code generation scopes form a stack
 // of active code generators.
 class CodeGeneratorScope BASE_EMBEDDED {
  public:
   explicit CodeGeneratorScope(CodeGenerator* cgen) {
     previous_ = top_;
     top_ = cgen;
   }
@@ skipping 246 matching lines @@
     PrintF("ArgumentsAccessStub (type %d)\n", type_);
   }
 #endif
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CODEGEN_H_