Don't use ConsStringIterator to compute string hashes

src/isolate.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ISOLATE_H_
 #define V8_ISOLATE_H_
 
 #include "include/v8-debug.h"
 #include "src/allocation.h"
 #include "src/assert-scope.h"
@@ skipping 944 matching lines @@
     has_installed_extensions_ = true;
   }
 
   bool has_installed_extensions() { return has_installed_extensions_; }
 
   unibrow::Mapping<unibrow::Ecma262Canonicalize>*
       regexp_macro_assembler_canonicalize() {
     return &regexp_macro_assembler_canonicalize_;
   }
 
+  uint16_t* cons_string_hashing_buffer() { return cons_string_hashing_buffer_; }
+
   RegExpStack* regexp_stack() { return regexp_stack_; }
 
   unibrow::Mapping<unibrow::Ecma262Canonicalize>*
       interp_canonicalize_mapping() {
     return &interp_canonicalize_mapping_;
   }
 
   Debug* debug() { return debug_; }
 
   inline bool DebuggerHasBreakPoints();
@@ skipping 282 matching lines @@
   EternalHandles* eternal_handles_;
   ThreadManager* thread_manager_;
   RuntimeState runtime_state_;
   Builtins builtins_;
   bool has_installed_extensions_;
   StringTracker* string_tracker_;
   unibrow::Mapping<unibrow::Ecma262UnCanonicalize> jsregexp_uncanonicalize_;
   unibrow::Mapping<unibrow::CanonicalizationRange> jsregexp_canonrange_;
   unibrow::Mapping<unibrow::Ecma262Canonicalize>
       regexp_macro_assembler_canonicalize_;
+  uint16_t* cons_string_hashing_buffer_;
   RegExpStack* regexp_stack_;
   DateCache* date_cache_;
   unibrow::Mapping<unibrow::Ecma262Canonicalize> interp_canonicalize_mapping_;
   CallInterfaceDescriptorData* call_descriptor_data_;
   base::RandomNumberGenerator* random_number_generator_;
 
   // Whether the isolate has been created for snapshotting.
   bool serializer_enabled_;
 
   // True if fatal error has been signaled for this isolate.
@@ skipping 276 matching lines @@
   }
 
   EmbeddedVector<char, 128> filename_;
   FILE* file_;
   int scope_depth_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ISOLATE_H_