SkPDF: Fix encoding of unichr outside of basic plane

src/pdf/SkPDFDevice.cpp

Index: src/pdf/SkPDFDevice.cpp
diff --git a/src/pdf/SkPDFDevice.cpp b/src/pdf/SkPDFDevice.cpp
index 12698dc00b012117466c1b4eb1cd00866f4516b0..7c366cdae7a6159d3605e127720b0bc263f4e295 100644
--- a/src/pdf/SkPDFDevice.cpp
+++ b/src/pdf/SkPDFDevice.cpp
@@ -1063,15 +1063,9 @@ static void write_wide_string(SkDynamicMemoryWStream* wStream,
                               bool wideChars) {
     if (wideChars) {
         SkASSERT(2 * len < 65535);
-        static const char gHex[] = "0123456789ABCDEF";
         wStream->writeText("<");
         for (size_t i = 0; i < len; i++) {
-            char result[4];  // Big-endian
-            result[0] = gHex[(input[i] >> 12) & 0xF];
-            result[1] = gHex[(input[i] >> 8) & 0xF];
-            result[2] = gHex[(input[i] >> 4) & 0xF];
-            result[3] = gHex[(input[i]) & 0xF];
-            wStream->write(result, 4);
+            SkPDFUtils::WriteUInt16BE(wStream, input[i]);
         }
         wStream->writeText(">");
     } else {