Debugger: use debug break slots to break at function exit.

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index 69c2871650e87b16abea5b6c8abd3f8522247236..9e04aaa7cca2447d665c872db882d65f7fe36159 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -1370,12 +1370,14 @@ static void Generate_KeyedStoreIC_PreMonomorphic_Strict(MacroAssembler* masm) {
 
 
 static void Generate_Return_DebugBreak(MacroAssembler* masm) {
-  DebugCodegen::GenerateReturnDebugBreak(masm);
+  DebugCodegen::GenerateDebugBreakStub(masm,
+                                       DebugCodegen::SAVE_RESULT_REGISTER);
 }
 
 
 static void Generate_Slot_DebugBreak(MacroAssembler* masm) {
-  DebugCodegen::GenerateSlotDebugBreak(masm);
+  DebugCodegen::GenerateDebugBreakStub(masm,
+                                       DebugCodegen::IGNORE_RESULT_REGISTER);
 }