Keep two empty lines between declarations for cpp files

src/cpu-profiler.cc

Index: src/cpu-profiler.cc
===================================================================
--- src/cpu-profiler.cc	(revision 15486)
+++ src/cpu-profiler.cc	(working copy)
@@ -423,6 +423,7 @@
   profiles_ = new CpuProfilesCollection();
 }
 
+
 void CpuProfiler::StartProfiling(const char* title, bool record_samples) {
   if (profiles_->StartProfiling(title, next_profile_uid_++, record_samples)) {
     StartProcessorIfNotStarted();