Support UseDartApi vm test on ARM.

runtime/vm/assembler_arm.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_ASSEMBLER_ARM_H_
 #define VM_ASSEMBLER_ARM_H_
 
 #ifndef VM_ASSEMBLER_H_
 #error Do not include assembler_arm.h directly; use assembler.h instead.
 #endif
@@ skipping 319 matching lines @@
   void Unimplemented(const char* message);
   void Untested(const char* message);
   void Unreachable(const char* message);
 
   static void InitializeMemoryWithBreakpoints(uword data, int length);
 
   void Comment(const char* format, ...) PRINTF_ATTRIBUTE(2, 3);
 
   const Code::Comments& GetCodeComments() const;
 
-  static const char* RegisterName(Register reg) {
-    UNIMPLEMENTED();
-    return NULL;
-  }
+  static const char* RegisterName(Register reg);
 
-  static const char* FpuRegisterName(FpuRegister reg) {
-    UNIMPLEMENTED();
-    return NULL;
-  }
+  static const char* FpuRegisterName(FpuRegister reg);
 
   // Data-processing instructions.
   void and_(Register rd, Register rn, ShifterOperand so, Condition cond = AL);
 
   void eor(Register rd, Register rn, ShifterOperand so, Condition cond = AL);
 
   void sub(Register rd, Register rn, ShifterOperand so, Condition cond = AL);
   void subs(Register rd, Register rn, ShifterOperand so, Condition cond = AL);
 
   void rsb(Register rd, Register rn, ShifterOperand so, Condition cond = AL);
@@ skipping 424 matching lines @@
     return *reg1 - *reg2;
   }
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(Assembler);
 };
 
 }  // namespace dart
 
 #endif  // VM_ASSEMBLER_ARM_H_