Teach debugger to ignore breakpoints

runtime/vm/debugger_x64.cc

 // 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.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/debugger.h"
 
 #include "vm/cpu.h"
 #include "vm/stub_code.h"
 
 namespace dart {
 
+// TODO(hausner): Implement this. For now just return null instead
+// of hitting UNIMPLEMENTED.
 RawInstance* ActivationFrame::GetLocalVarValue(intptr_t slot_index) {
-  UNIMPLEMENTED();
-  return NULL;
+  return Instance::null();
 }
 
 
 RawInstance* ActivationFrame::GetInstanceCallReceiver(
                  intptr_t num_actual_args) {
   ASSERT(num_actual_args > 0);  // At minimum we have a receiver on the stack.
   // Stack pointer points to last argument that was pushed on the stack.
   uword receiver_addr = sp() + ((num_actual_args - 1) * kWordSize);
   return reinterpret_cast<RawInstance*>(
              *reinterpret_cast<uword*>(receiver_addr));
@@ skipping 38 matching lines @@
   code[9] = 0x90;  // nop
   code[10] = 0x90;  // nop
   code[11] = 0x90;  // nop
   code[12] = 0x90;  // nop
   CPU::FlushICache(pc_, 5);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64