Extract hardcoded error strings into a single place and replace them with enum.

test/cctest/test-code-stubs-ia32.cc

 // Copyright 2013 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 76 matching lines @@
   // Call through to the actual stub
   __ call(start, RelocInfo::EXTERNAL_REFERENCE);
 
   __ add(esp, Immediate(kDoubleSize));
 
   // Make sure no registers have been unexpectedly clobbered
   for (--reg_num; reg_num >= 0; --reg_num) {
     Register reg = Register::from_code(reg_num);
     if (!reg.is(esp) && !reg.is(ebp) && !reg.is(destination_reg)) {
       __ cmp(reg, MemOperand(esp, 0));
-      __ Assert(equal, "register was clobbered");
+      __ Assert(equal, kRegisterWasClobbered);
       __ add(esp, Immediate(kPointerSize));
     }
   }
 
   __ mov(eax, destination_reg);
 
   __ pop(edi);
   __ pop(esi);
   __ pop(edx);
   __ pop(ecx);
@@ skipping 64 matching lines @@
   RunAllTruncationTests(MakeConvertDToIFuncTrampoline(isolate, esi, edx));
   RunAllTruncationTests(MakeConvertDToIFuncTrampoline(isolate, esi, edi));
   RunAllTruncationTests(MakeConvertDToIFuncTrampoline(isolate, esi, esi));
   RunAllTruncationTests(MakeConvertDToIFuncTrampoline(isolate, edi, eax));
   RunAllTruncationTests(MakeConvertDToIFuncTrampoline(isolate, edi, ebx));
   RunAllTruncationTests(MakeConvertDToIFuncTrampoline(isolate, edi, ecx));
   RunAllTruncationTests(MakeConvertDToIFuncTrampoline(isolate, edi, edx));
   RunAllTruncationTests(MakeConvertDToIFuncTrampoline(isolate, edi, edi));
   RunAllTruncationTests(MakeConvertDToIFuncTrampoline(isolate, edi, esi));
 }