[debugger] Refactor LiveEdit function info collection

src/debug/liveedit.h

Index: src/debug/liveedit.h
diff --git a/src/debug/liveedit.h b/src/debug/liveedit.h
index 4edd5831823beaf6ef3bd92cb0cab47ce3bab01e..af740437277174b3a0135883e9d0a0b90871db39 100644
--- a/src/debug/liveedit.h
+++ b/src/debug/liveedit.h
@@ -32,25 +32,39 @@ namespace v8 {
 namespace internal {
 
 // This class collects some specific information on structure of functions
-// in a particular script. It gets called from compiler all the time, but
-// actually records any data only when liveedit operation is in process;
-// in any other time this class is very cheap.
+// in a particular script.
 //
 // The primary interest of the Tracker is to record function scope structures
-// in order to analyze whether function code maybe safely patched (with new
+// in order to analyze whether function code may be safely patched (with new
 // code successfully reading existing data from function scopes). The Tracker
 // also collects compiled function codes.
-class LiveEditFunctionTracker {
+class LiveEditFunctionTracker : public AstTraversalVisitor {
  public:
-  explicit LiveEditFunctionTracker(Isolate* isolate, FunctionLiteral* fun);
-  ~LiveEditFunctionTracker();
-  void RecordFunctionInfo(Handle<SharedFunctionInfo> info,
-                          FunctionLiteral* lit, Zone* zone);
+  // Traverses the entire AST, and records information about all
+  // FunctionLiterals for further use by LiveEdit code patching. The collected
+  // information is returned as a serialized array.
+  static Handle<JSArray> Collect(FunctionLiteral* node, Handle<Script> script,
+                                 Zone* zone, Isolate* isolate);
 
-  static bool IsActive(Isolate* isolate);
+  virtual ~LiveEditFunctionTracker() {}
+  void VisitFunctionLiteral(FunctionLiteral* node) override;
 
  private:
+  LiveEditFunctionTracker(Handle<Script> script, Zone* zone, Isolate* isolate);
+
+  void FunctionStarted(FunctionLiteral* fun);
+  void FunctionDone(Handle<SharedFunctionInfo> shared, Scope* scope);
+  Handle<Object> SerializeFunctionScope(Scope* scope);
+
+  Handle<Script> script_;
+  Zone* zone_;
   Isolate* isolate_;
+
+  Handle<JSArray> result_;
+  int len_;
+  int current_parent_index_;
+
+  DISALLOW_COPY_AND_ASSIGN(LiveEditFunctionTracker);
 };