Intrinsify OnebyteString's hashcode. Next step is to inline it.

runtime/vm/object.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/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/bigint_operations.h"
@@ skipping 10451 matching lines @@
   Zone* zone = Isolate::Current()->current_zone();
   return zone->AllocUnsafe(size);
 }
 
 
 const char* Bigint::ToCString() const {
   return BigintOperations::ToDecimalCString(*this, &BigintAllocator);
 }
 
 
+// Synchronize with implementation in compiler (intrinsifier).
 class StringHasher : ValueObject {
  public:
   StringHasher() : hash_(0) {}
   void Add(int32_t ch) {
     hash_ += ch;
     hash_ += hash_ << 10;
     hash_ ^= hash_ >> 6;
   }
   // Return a non-zero hash of at most 'bits' bits.
   intptr_t Finalize(int bits) {
@@ skipping 2624 matching lines @@
   }
   return result.raw();
 }
 
 
 const char* WeakProperty::ToCString() const {
   return "_WeakProperty";
 }
 
 }  // namespace dart