Fix a potential crash bug in keyed calls for non-string keys.

src/arm/macro-assembler-arm.h

 // Copyright 2010 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
@@ skipping 773 matching lines @@
   }
   // Jump if either of the registers contain a non-smi.
   void JumpIfNotBothSmi(Register reg1, Register reg2, Label* on_not_both_smi);
   // Jump if either of the registers contain a smi.
   void JumpIfEitherSmi(Register reg1, Register reg2, Label* on_either_smi);
 
   // Abort execution if argument is a smi. Used in debug code.
   void AbortIfSmi(Register object);
   void AbortIfNotSmi(Register object);
 
+  // Abort execution if argument is a string. Used in debug code.
+  void AbortIfNotString(Register object);
+
   // Abort execution if argument is not the root value with the given index.
   void AbortIfNotRootValue(Register src,
                            Heap::RootListIndex root_value_index,
                            const char* message);
 
   // ---------------------------------------------------------------------------
   // HeapNumber utilities
 
   void JumpIfNotHeapNumber(Register object,
                            Register heap_number_map,
@@ skipping 137 matching lines @@
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_MACRO_ASSEMBLER_ARM_H_