Do fewer encoding checks in FlatStringReader used in the JSON stringifier.

src/objects.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_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 9383 matching lines @@
 
 // A flat string reader provides random access to the contents of a
 // string independent of the character width of the string.  The handle
 // must be valid as long as the reader is being used.
 class FlatStringReader : public Relocatable {
  public:
   FlatStringReader(Isolate* isolate, Handle<String> str);
   FlatStringReader(Isolate* isolate, Vector<const char> input);
   void PostGarbageCollection();
   inline uc32 Get(int index);
+  template <typename Char>
+  inline Char Get(int index);
   int length() { return length_; }
  private:
   String** str_;
   bool is_one_byte_;
   int length_;
   const void* start_;
 };
 
 
 // This maintains an off-stack representation of the stack frames required
@@ skipping 1558 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_