Fix syntax error, feel sheepish.

src/hydrogen.cc

 // Copyright 2011 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 3749 matching lines @@
   }
   AddInstruction(new HBoundsCheck(key, length));
   return new HStoreKeyedFastElement(elements, key, val);
 }
 
 
 HInstruction* HGraphBuilder::BuildStoreKeyedPixelArrayElement(
     HValue* object,
     HValue* key,
     HValue* val,
-    XExpression* expr) {
+    Expression* expr) {
   ASSERT(expr->IsMonomorphic());
   AddInstruction(new HCheckNonSmi(object));
   Handle<Map> map = expr->GetMonomorphicReceiverType();
   ASSERT(!map->has_fast_elements());
   ASSERT(map->has_pixel_array_elements());
   AddInstruction(new HCheckMap(object, map));
   HLoadElements* elements = new HLoadElements(object);
   AddInstruction(elements);
   HInstruction* length = AddInstruction(new HPixelArrayLength(elements));
   AddInstruction(new HBoundsCheck(key, length));
@@ skipping 2232 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal