Keep two empty lines between declarations for cpp files

src/preparser.cc

Index: src/preparser.cc
===================================================================
--- src/preparser.cc	(revision 15486)
+++ src/preparser.cc	(working copy)
@@ -1685,6 +1685,7 @@
   return result;
 }
 
+
 bool PreParser::peek_any_identifier() {
   i::Token::Value next = peek();
   return next == i::Token::IDENTIFIER ||
@@ -1698,6 +1699,7 @@
   return AddSymbol(i::Vector<const byte>::cast(key), true, value);
 }
 
+
 int DuplicateFinder::AddUtf16Symbol(i::Vector<const uint16_t> key, int value) {
   return AddSymbol(i::Vector<const byte>::cast(key), false, value);
 }