Revert "- Use a hash table to canonicalize instances/arrays to avoid having to iterate over a linea…

runtime/vm/snapshot.cc

 // Copyright (c) 2012, 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.
 
 #include "vm/snapshot.h"
 
 #include "platform/assert.h"
 #include "vm/bootstrap.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
@@ skipping 524 matching lines @@
       // we need to initialize any remaining padding area with the Null object.
       while (offset < instance_size) {
         result->SetFieldAtOffset(offset, Object::null_object());
         offset += kWordSize;
       }
     }
     if (RawObject::IsCanonical(tags)) {
       if (kind_ == Snapshot::kFull) {
         result->SetCanonical();
       } else {
-        *result = result->CheckAndCanonicalize(thread(), NULL);
+        *result = result->CheckAndCanonicalize(NULL);
         ASSERT(!result->IsNull());
       }
     }
   }
   return result->raw();
 }
 
 
 void SnapshotReader::AddBackRef(intptr_t id,
                                 Object* obj,
@@ skipping 2110 matching lines @@
   if (setjmp(*jump.Set()) == 0) {
     NoSafepointScope no_safepoint;
     WriteObject(obj.raw());
   } else {
     ThrowException(exception_type(), exception_msg());
   }
 }
 
 
 }  // namespace dart