factor out hexadecimal constants.

Now we don't have to rely on the linker to de-duplicate
so many gHex[] constants.

Change-Id: Ia86d3a92648415afdb8d29499b4faded5ed05c7d
Reviewed-on: https://skia-review.googlesource.com/20180
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
diff --git a/src/core/SkString.cpp b/src/core/SkString.cpp
index 528c602..8eee127 100644
--- a/src/core/SkString.cpp
+++ b/src/core/SkString.cpp
@@ -539,13 +539,11 @@
 void SkString::insertHex(size_t offset, uint32_t hex, int minDigits) {
     minDigits = SkTPin(minDigits, 0, 8);
 
-    static const char gHex[] = "0123456789ABCDEF";
-
     char    buffer[8];
     char*   p = buffer + sizeof(buffer);
 
     do {
-        *--p = gHex[hex & 0xF];
+        *--p = SkHexadecimalDigits::gUpper[hex & 0xF];
         hex >>= 4;
         minDigits -= 1;
     } while (hex != 0);