Support 'restart call frame' debug command

src/liveedit-debugger.js

-// Copyright 2010 the V8 project authors. All rights reserved.
+// Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
@@ skipping 28 matching lines @@
 // create a new instance of this function goes away. An old version of script
 // is created to back up this obsolete function.
 // All unchanged functions have their positions updated accordingly.
 //
 // LiveEdit namespace is declared inside a single function constructor.
 Debug.LiveEdit = new function() {
 
   // Forward declaration for minifier.
   var FunctionStatus;
 
+  var NEEDS_STEP_IN_PROPERTY_NAME = "stack_update_needs_step_in";
+
   // Applies the change to the script.
   // The change is in form of list of chunks encoded in a single array as
   // a series of triplets (pos1_start, pos1_end, pos2_end)
   function ApplyPatchMultiChunk(script, diff_array, new_source, preview_only,
       change_log) {
 
     var old_source = script.source;
 
     // Gather compile information about old version of script.
     var old_compile_info = GatherCompileInfo(old_source, script);
@@ skipping 94 matching lines @@
     // Committing all changes.
 
     // Check that function being patched is not currently on stack or drop them.
     var dropped_functions_number =
         CheckStackActivations(replaced_function_infos, change_log);
 
     preview_description.stack_modified = dropped_functions_number != 0;
 
     // Our current implementation requires client to manually issue "step in"
     // command for correct stack state.
-    preview_description.stack_update_needs_step_in =
+    preview_description[NEEDS_STEP_IN_PROPERTY_NAME] =
         preview_description.stack_modified;
 
     // Start with breakpoints. Convert their line/column positions and
     // temporary remove.
     var break_points_restorer = TemporaryRemoveBreakPoints(script, change_log);
 
     var old_script;
 
     // Create an old script only if there are function that should be linked
     // to old version.
@@ skipping 896 matching lines @@
     function DescribePositions(node) {
       return {
         start_position: node.info.start_position,
         end_position: node.info.end_position
       };
     }
 
     return ProcessOldNode(old_code_tree);
   }
 
+  // Restarts call frame and returns value similar to what LiveEdit returns.
+  function RestartFrame(frame_mirror) {
+    var result = frame_mirror.restart();
+    if (IS_STRING(result)) {
+      throw new Failure("Failed to restart frame: " + result);
+    }
+    var result = {};
+    result[NEEDS_STEP_IN_PROPERTY_NAME] = true;
+    return result;
+  }
+  // Function is public.
+  this.RestartFrame = RestartFrame;
 
   // Functions are public for tests.
   this.TestApi = {
     PosTranslator: PosTranslator,
     CompareStrings: CompareStrings,
     ApplySingleChunkPatch: ApplySingleChunkPatch
   };
 };