[Interpreter] Adds support to fetch return value on break at return.

src/runtime/runtime-debug.cc

Index: src/runtime/runtime-debug.cc
diff --git a/src/runtime/runtime-debug.cc b/src/runtime/runtime-debug.cc
index 631f5e8153e82538bfc19c170749b78ce836f504..d5cfaf363014ebc041dc7b0d08eea7e00d68d6f1 100644
--- a/src/runtime/runtime-debug.cc
+++ b/src/runtime/runtime-debug.cc
@@ -18,7 +18,7 @@ namespace internal {
 
 RUNTIME_FUNCTION(Runtime_DebugBreak) {
   SealHandleScope shs(isolate);
-  DCHECK(args.length() == 0);
+  DCHECK(args.length() == 1);
   // Get the top-most JavaScript frame.
   JavaScriptFrameIterator it(isolate);
   isolate->debug()->Break(args, it.frame());
@@ -591,31 +591,7 @@ RUNTIME_FUNCTION(Runtime_GetFrameDetails) {
   // to the frame information.
   Handle<Object> return_value = isolate->factory()->undefined_value();
   if (at_return) {
-    StackFrameIterator it2(isolate);
-    Address internal_frame_sp = NULL;
-    while (!it2.done()) {
-      if (it2.frame()->is_internal()) {
-        internal_frame_sp = it2.frame()->sp();
-      } else {
-        if (it2.frame()->is_java_script()) {
-          if (it2.frame()->id() == it.frame()->id()) {
-            // The internal frame just before the JavaScript frame contains the
-            // value to return on top. A debug break at return will create an
-            // internal frame to store the return value (eax/rax/r0) before
-            // entering the debug break exit frame.
-            if (internal_frame_sp != NULL) {
-              return_value =
-                  Handle<Object>(Memory::Object_at(internal_frame_sp), isolate);
-              break;
-            }
-          }
-        }
-
-        // Indicate that the previous frame was not an internal frame.
-        internal_frame_sp = NULL;
-      }
-      it2.Advance();
-    }
+    return_value = isolate->debug()->get_return_value();
   }
 
   // Now advance to the arguments adapter frame (if any). It contains all