Very first steps for a debugger

runtime/vm/debugger.h

Index: runtime/vm/debugger.h
===================================================================
--- runtime/vm/debugger.h	(revision 0)
+++ runtime/vm/debugger.h	(revision 0)
@@ -0,0 +1,42 @@
+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#ifndef VM_DEBUGGER_H_
+#define VM_DEBUGGER_H_
+
+#include "vm/object.h"
+
+namespace dart {
+
+class Breakpoint;
+class Isolate;
+class ObjectPointerVisitor;
+
+class Debugger {
+ public:
+  Debugger();
+
+  void Initialize(Isolate* isolate);
+
+  // Set breakpoint at closest location to function entry.
+  void SetBreakpointAtEntry(const String& class_name,
+                            const String& function_name);
+
+  void VisitObjectPointers(ObjectPointerVisitor* visitor);
+
+  // Returns NULL if no breakpoint exists for the given address.
+  Breakpoint* GetBreakpoint(uword breakpoint_address);
+
+ private:
+  void AddBreakpoint(Breakpoint* bpt);
+
+  bool initialized_;
+  Breakpoint* breakpoints_;
+  DISALLOW_COPY_AND_ASSIGN(Debugger);
+};
+
+
+}  // namespace dart
+
+#endif  // VM_DEBUGGER_H_