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

src/builtins.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 10 matching lines @@
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef V8_BUILTINS_H_
 #define V8_BUILTINS_H_
 
-namespace v8 { namespace internal {
+namespace v8 {
+namespace internal {
 
 // Define list of builtins implemented in C.
 #define BUILTIN_LIST_C(V)                          \
   V(Illegal)                                       \
                                                    \
   V(EmptyFunction)                                 \
                                                    \
   V(ArrayCode)                                     \
                                                    \
   V(ArrayPush)                                     \
@@ skipping 171 matching lines @@
   static void Generate_JSConstructEntryTrampoline(MacroAssembler* masm);
   static void Generate_ArgumentsAdaptorTrampoline(MacroAssembler* masm);
 
   static void Generate_FunctionCall(MacroAssembler* masm);
   static void Generate_FunctionApply(MacroAssembler* masm);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_BUILTINS_H_