Get rid of duplicated CPU::DebugBreak() method.

src/runtime.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 12954 matching lines @@
   RUNTIME_ASSERT(compilation_state == Script::COMPILATION_STATE_INITIAL);
   script->set_source(*source);
 
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SystemBreak) {
   SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
-  CPU::DebugBreak();
+  OS::DebugBreak();
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugDisassembleFunction) {
   HandleScope scope(isolate);
 #ifdef DEBUG
   ASSERT(args.length() == 1);
   // Get the function and make sure it is compiled.
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, func, 0);
@@ skipping 1650 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal