Revert 11927 "Fix liveedit heap traversal bug with write barrier"

src/liveedit.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 950 matching lines @@
  private:
   Code* original_;
   Code* substitution_;
 };
 
 
 // Finds all references to original and replaces them with substitution.
 static void ReplaceCodeObject(Code* original, Code* substitution) {
   ASSERT(!HEAP->InNewSpace(substitution));
 
-  // Perform a full GC in order to ensure that we are not in the middle of an
-  // incremental marking phase when we are replacing the code object.
-  // Since we are not in an incremental marking phase we can write pointers
-  // to code objects (that are never in new space) without worrying about
-  // write barriers.
-  HEAP->CollectAllGarbage(Heap::kMakeHeapIterableMask,
-                          "liveedit.cc ReplaceCodeObject");
-
   AssertNoAllocation no_allocations_please;
 
   ReplacingVisitor visitor(original, substitution);
 
   // Iterate over all roots. Stack frames may have pointer into original code,
   // so temporary replace the pointers with offset numbers
   // in prologue/epilogue.
   HEAP->IterateRoots(&visitor, VISIT_ALL);
 
   // Now iterate over all pointers of all objects, including code_target
@@ skipping 898 matching lines @@
 
 bool LiveEditFunctionTracker::IsActive(Isolate* isolate) {
   return false;
 }
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 
 
 } }  // namespace v8::internal