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

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index e53df91d0ba67f99ba9bb1f422a4b68ff9fed72d..ed287b5efbef9ff6b8f9e745f15b70282d321d76 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -10763,11 +10763,9 @@ void ObjectVisitor::VisitCell(RelocInfo* rinfo) {
 
 
 void ObjectVisitor::VisitDebugTarget(RelocInfo* rinfo) {
-  DCHECK((RelocInfo::IsJSReturn(rinfo->rmode()) &&
-          rinfo->IsPatchedReturnSequence()) ||
-         (RelocInfo::IsDebugBreakSlot(rinfo->rmode()) &&
-          rinfo->IsPatchedDebugBreakSlotSequence()));
-  Object* target = Code::GetCodeFromTargetAddress(rinfo->call_address());
+  DCHECK(RelocInfo::IsDebugBreakSlot(rinfo->rmode()) &&
+         rinfo->IsPatchedDebugBreakSlotSequence());
+  Object* target = Code::GetCodeFromTargetAddress(rinfo->debug_call_address());
   Object* old_target = target;
   VisitPointer(&target);
   CHECK_EQ(target, old_target);  // VisitPointer doesn't change Code* *target.