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

src/v8-counters.h

 // Copyright 2007-2008 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 12 matching lines @@
 // 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_V8_COUNTERS_H_
 #define V8_V8_COUNTERS_H_
 
 #include "counters.h"
 
-namespace v8 { namespace internal {
+namespace v8 {
+namespace internal {
 
 #define HISTOGRAM_TIMER_LIST(HT)                                      \
   /* Garbage collection timers. */                                    \
   HT(gc_compactor, V8.GCCompactor)                                    \
   HT(gc_scavenger, V8.GCScavenger)                                    \
   HT(gc_context, V8.GCContext) /* GC context cleanup time */          \
   /* Parsing timers. */                                               \
   HT(parse, V8.Parse)                                                 \
   HT(parse_lazy, V8.ParseLazy)                                        \
   HT(pre_parse, V8.PreParse)                                          \
@@ skipping 123 matching lines @@
     stats_counter_count
   };
 
   // Sliding state window counters.
   static StatsCounter state_counters[];
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_V8_COUNTERS_H_