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

src/shell.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 14 matching lines @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 //
 // A simple interactive shell.  Enable with --shell.
 
 #ifndef V8_SHELL_H_
 #define V8_SHELL_H_
 
 #include "../public/debug.h"
 
-namespace v8 { namespace internal {
+namespace v8 {
+namespace internal {
 
 // Debug event handler for interactive debugging.
 void handle_debug_event(v8::DebugEvent event,
                         v8::Handle<v8::Object> exec_state,
                         v8::Handle<v8::Object> event_data,
                         v8::Handle<Value> data);
 
 
 class Shell {
  public:
   static void PrintObject(v8::Handle<v8::Value> obj);
   // Run the read-eval loop, executing code in the specified
   // environment.
   static void Run(v8::Handle<v8::Context> context);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_SHELL_H_