Keep two empty lines between declarations for cpp files

src/frames.cc

Index: src/frames.cc
===================================================================
--- src/frames.cc	(revision 15486)
+++ src/frames.cc	(working copy)
@@ -202,6 +202,7 @@
   }
 }
 
+
 bool StackTraceFrameIterator::IsValidFrame() {
     if (!frame()->function()->IsJSFunction()) return false;
     Object* script = JSFunction::cast(frame()->function())->shared()->script();
@@ -1568,6 +1569,7 @@
   ASSERT(i == kNumJSCallerSaved);
 }
 
+
 int JSCallerSavedCode(int n) {
   ASSERT(0 <= n && n < kNumJSCallerSaved);
   return caller_saved_code_data.reg_code[n];
@@ -1600,6 +1602,7 @@
   return NULL;
 }
 
+
 Vector<StackFrame*> CreateStackMap(Isolate* isolate, Zone* zone) {
   ZoneList<StackFrame*> list(10, zone);
   for (StackFrameIterator it(isolate); !it.done(); it.Advance()) {