More precise break points and stepping when debugging...

src/builtins.cc

Index: src/builtins.cc
===================================================================
--- src/builtins.cc	(revision 4816)
+++ src/builtins.cc	(working copy)
@@ -1360,10 +1360,17 @@
   Debug::GenerateStubNoRegistersDebugBreak(masm);
 }
 
+
+static void Generate_Slot_DebugBreak(MacroAssembler* masm) {
+  Debug::GenerateSlotDebugBreak(masm);
+}
+
+
 static void Generate_PlainReturn_LiveEdit(MacroAssembler* masm) {
   Debug::GeneratePlainReturnLiveEdit(masm);
 }
 
+
 static void Generate_FrameDropper_LiveEdit(MacroAssembler* masm) {
   Debug::GenerateFrameDropperLiveEdit(masm);
 }