Introduce ENABLE_LATIN_1 compile flag

src/scanner.h

 // 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 165 matching lines @@
 
   ~LiteralBuffer() {
     if (backing_store_.length() > 0) {
       backing_store_.Dispose();
     }
   }
 
   INLINE(void AddChar(uint32_t code_unit)) {
     if (position_ >= backing_store_.length()) ExpandBuffer();
     if (is_ascii_) {
-      if (code_unit < kMaxAsciiCharCodeU) {
+      if (code_unit <= unibrow::Latin1::kMaxChar) {
         backing_store_[position_] = static_cast<byte>(code_unit);
-        position_ += kASCIISize;
+        position_ += kOneByteSize;
         return;
       }
       ConvertToUtf16();
     }
     ASSERT(code_unit < 0x10000u);
     *reinterpret_cast<uc16*>(&backing_store_[position_]) = code_unit;
     position_ += kUC16Size;
   }
 
   bool is_ascii() { return is_ascii_; }
@@ skipping 44 matching lines @@
     ASSERT(is_ascii_);
     Vector<byte> new_store;
     int new_content_size = position_ * kUC16Size;
     if (new_content_size >= backing_store_.length()) {
       // Ensure room for all currently read code units as UC16 as well
       // as the code unit about to be stored.
       new_store = Vector<byte>::New(NewCapacity(new_content_size));
     } else {
       new_store = backing_store_;
     }
-    char* src = reinterpret_cast<char*>(backing_store_.start());
+    uint8_t* src = backing_store_.start();
     uc16* dst = reinterpret_cast<uc16*>(new_store.start());
     for (int i = position_ - 1; i >= 0; i--) {
       dst[i] = src[i];
     }
     if (new_store.start() != backing_store_.start()) {
       backing_store_.Dispose();
       backing_store_ = new_store;
     }
     position_ = new_content_size;
     is_ascii_ = false;
@@ skipping 297 matching lines @@
   bool has_multiline_comment_before_next_;
   // Whether we scan 'let' as a keyword for harmony block-scoped let bindings.
   bool harmony_scoping_;
   // Whether we scan 'module', 'import', 'export' as keywords.
   bool harmony_modules_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_SCANNER_H_