Change scanner buffers to not use utf-8.

src/globals.h

Index: src/globals.h
diff --git a/src/globals.h b/src/globals.h
index 35156ae60666b388c7fb33f82fb78c1ebf9b0106..9b24bf63503b9a8a0d4258b43bcc1e5ab193130c 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -181,10 +181,6 @@ typedef byte* Address;
 #define USING_BSD_ABI
 #endif
 
-// Code-point values in Unicode 4.0 are 21 bits wide.
-typedef uint16_t uc16;
-typedef int32_t uc32;
-
 // -----------------------------------------------------------------------------
 // Constants
 
@@ -228,6 +224,15 @@ const int kBinary32MinExponent  = 0x01;
 const int kBinary32MantissaBits = 23;
 const int kBinary32ExponentShift = 23;
 
+// ASCII/UC16 constants
+// Code-point values in Unicode 4.0 are 21 bits wide.
+typedef uint16_t uc16;
+typedef int32_t uc32;
+const int kASCIISize    = kCharSize;
+const int kUC16Size     = sizeof(uc16);      // NOLINT
+const uc32 kMaxAsciiCharCode = 0x7f;
+const uint32_t kMaxAsciiCharCodeU = 0x7fu;
+
 
 // The expression OFFSET_OF(type, field) computes the byte-offset
 // of the specified field relative to the containing type. This