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

src/mips/debug-mips.cc

 // Copyright 2012 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 124 matching lines @@
     ASSERT((object_regs & ~kJSCallerSaved) == 0);
     ASSERT((non_object_regs & ~kJSCallerSaved) == 0);
     ASSERT((object_regs & non_object_regs) == 0);
     if ((object_regs | non_object_regs) != 0) {
       for (int i = 0; i < kNumJSCallerSaved; i++) {
         int r = JSCallerSavedCode(i);
         Register reg = { r };
         if ((non_object_regs & (1 << r)) != 0) {
           if (FLAG_debug_code) {
             __ And(at, reg, 0xc0000000);
-            __ Assert(
-                eq, "Unable to encode value as smi", at, Operand(zero_reg));
+            __ Assert(eq, kUnableToEncodeValueAsSmi, at, Operand(zero_reg));
           }
           __ sll(reg, reg, kSmiTagSize);
         }
       }
       __ MultiPush(object_regs | non_object_regs);
     }
 
 #ifdef DEBUG
     __ RecordComment("// Calling from debug break to runtime - come in - over");
 #endif
@@ skipping 161 matching lines @@
 
 
 void Debug::GenerateSlotDebugBreak(MacroAssembler* masm) {
   // In the places where a debug break slot is inserted no registers can contain
   // object pointers.
   Generate_DebugBreakCallHelper(masm, 0, 0);
 }
 
 
 void Debug::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
-  masm->Abort("LiveEdit frame dropping is not supported on mips");
+  masm->Abort(kLiveEditFrameDroppingIsNotSupportedOnMips);
 }
 
 
 void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
-  masm->Abort("LiveEdit frame dropping is not supported on mips");
+  masm->Abort(kLiveEditFrameDroppingIsNotSupportedOnMips);
 }
 
 
 const bool Debug::kFrameDropperSupported = false;
 
 #undef __
 
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS