ARM and MIPS changes which correspond to the initial change submitted in

runtime/vm/stack_frame_mips.h

 // Copyright (c) 2013, 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_STACK_FRAME_MIPS_H_
 #define VM_STACK_FRAME_MIPS_H_
 
 namespace dart {
 
 /* MIPS Dart Frame Layout
@@ skipping 12 matching lines @@
                +--------------------+
 Caller frame   | last parameter     | <- SP of caller frame
                |  ...               |
 
                T against a slot indicates it needs to be traversed during GC.
 */
 
 static const int kDartFrameFixedSize = 4;  // PP, FP, RA, PC marker.
 static const int kSavedPcSlotFromSp = -2;
 
-static const int kFirstObjectSlotFromFp = -2;  // Used by GC to traverse stack.
+static const int kFirstObjectSlotFromFp = -1;  // Used by GC to traverse stack.
 
 static const int kFirstLocalSlotFromFp = -2;
 static const int kSavedCallerPpSlotFromFp = -1;
 static const int kSavedCallerFpSlotFromFp = 0;
 static const int kSavedCallerPcSlotFromFp = 1;
 static const int kPcMarkerSlotFromFp = 2;
 static const int kParamEndSlotFromFp = 2;  // One slot past last parameter.
 static const int kCallerSpSlotFromFp = 3;
 
 // Entry and exit frame layout.
 static const int kSavedContextSlotFromEntryFp = -23;
 static const int kExitLinkSlotFromEntryFp = -22;
 
 }  // namespace dart
 
 #endif  // VM_STACK_FRAME_MIPS_H_