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

src/debug.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 23 matching lines @@
 #include "execution.h"
 #include "factory.h"
 #include "hashmap.h"
 #include "platform.h"
 #include "string-stream.h"
 #include "v8threads.h"
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
 #include "../include/v8-debug.h"
 
-namespace v8 { namespace internal {
+namespace v8 {
+namespace internal {
 
 
 // Forward declarations.
 class EnterDebugger;
 
 
 // Step actions. NOTE: These values are in macros.py as well.
 enum StepAction {
   StepNone = -1,  // Stepping not prepared.
   StepOut = 0,   // Step out of the current function.
@@ skipping 763 matching lines @@
   Debug::AddressId id_;
   int reg_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 #endif  // V8_DEBUG_H_