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

src/ast.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 19 matching lines @@
 
 #include "execution.h"
 #include "factory.h"
 #include "runtime.h"
 #include "token.h"
 #include "variables.h"
 #include "macro-assembler.h"
 #include "jsregexp.h"
 #include "jump-target.h"
 
-namespace v8 { namespace internal {
+namespace v8 {
+namespace internal {
 
 // The abstract syntax tree is an intermediate, light-weight
 // representation of the parsed JavaScript code suitable for
 // compilation to native code.
 
 // Nodes are allocated in a separate zone, which allows faster
 // allocation and constant-time deallocation of the entire syntax
 // tree.
 
 
@@ skipping 1657 matching lines @@
 #undef DEF_VISIT
 
  private:
   bool stack_overflow_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_