Replace the use CharacterStreams in Heap::AllocateSymbolInternal and String::ComputeHash

src/heap.h

 // 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 746 matching lines @@
                                                      uint32_t hash_field);
 
   MUST_USE_RESULT inline MaybeObject* AllocateAsciiSymbol(
         Vector<const char> str,
         uint32_t hash_field);
 
   MUST_USE_RESULT inline MaybeObject* AllocateTwoByteSymbol(
         Vector<const uc16> str,
         uint32_t hash_field);
 
+  template<typename T>
+  static inline bool IsOneByte(T t, int chars);
+
+  template<typename T>
+  MUST_USE_RESULT inline MaybeObject* AllocateInternalSymbol(
+      T t, int chars, uint32_t hash_field);
+
+  template<bool is_one_byte, typename T>
   MUST_USE_RESULT MaybeObject* AllocateInternalSymbol(
-      unibrow::CharacterStream* buffer, int chars, uint32_t hash_field);
-
-  MUST_USE_RESULT MaybeObject* AllocateExternalSymbol(
-      Vector<const char> str,
-      int chars);
+      T t, int chars, uint32_t hash_field);
 
   // Allocates and partially initializes a String.  There are two String
   // encodings: ASCII and two byte.  These functions allocate a string of the
   // given length and set its map and length fields.  The characters of the
   // string are uninitialized.
   // Returns Failure::RetryAfterGC(requested_bytes, space) if the allocation
   // failed.
   // Please note this does not perform a garbage collection.
   MUST_USE_RESULT MaybeObject* AllocateRawOneByteString(
       int length,
@@ skipping 2096 matching lines @@
   AssertNoAllocation no_alloc;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_