Revert OneByteString back to ISO Latin-1 instead of ASCII

runtime/vm/unicode.h

 // Copyright (c) 2011, 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.
 
 #ifndef VM_UNICODE_H_
 #define VM_UNICODE_H_
 
 #include "vm/allocation.h"
 #include "vm/globals.h"
 
 namespace dart {
 
 class String;
 
 class Utf8 : AllStatic {
  public:
   enum Type {
-    kAscii = 0,  // ASCII character set.
+    kLatin1 = 0,  // Latin-1 character set.
     kBMP,  // Basic Multilingual Plane.
     kSMP,  // Supplementary Multilingual Plane.
   };
 
   static const intptr_t kMaxOneByteChar   = 0x7F;
   static const intptr_t kMaxTwoByteChar   = 0x7FF;
   static const intptr_t kMaxThreeByteChar = 0xFFFF;
   static const intptr_t kMaxFourByteChar  = 0x10FFFF;
   static const intptr_t kMaxBmpCodepoint  = 0xffff;
   static const int32_t kLeadOffset = (0xD800 - (0x10000 >> 10));
@@ skipping 10 matching lines @@
   static intptr_t Length(int32_t ch);
   static intptr_t Length(const String& str);
 
   static intptr_t Encode(int32_t ch, char* dst);
   static intptr_t Encode(const String& src, char* dst, intptr_t len);
 
   static intptr_t Decode(const uint8_t* utf8_array,
                          intptr_t array_len,
                          int32_t* ch);
 
-  static bool DecodeToAscii(const uint8_t* utf8_array,
-                            intptr_t array_len,
-                            uint8_t* dst,
-                            intptr_t len);
+  static bool DecodeToLatin1(const uint8_t* utf8_array,
+                             intptr_t array_len,
+                             uint8_t* dst,
+                             intptr_t len);
   static bool DecodeToUTF16(const uint8_t* utf8_array,
                             intptr_t array_len,
                             uint16_t* dst,
                             intptr_t len);
   static bool DecodeToUTF32(const uint8_t* utf8_array,
                             intptr_t array_len,
                             uint32_t* dst,
                             intptr_t len);
   static bool DecodeCStringToUTF32(const char* str,
                                    uint32_t* dst,
@@ skipping 65 matching lines @@
   // Data for small code points with one mapping
   static const int16_t stage2_[];
 
   // Data for large code points or code points with both mappings.
   static const int32_t stage2_exception_[][2];
 };
 
 }  // namespace dart
 
 #endif  // VM_UNICODE_H_