SkPDF: Implement /ActualText to make text extraction correct.

src/pdf/SkPDFUtils.h

Index: src/pdf/SkPDFUtils.h
diff --git a/src/pdf/SkPDFUtils.h b/src/pdf/SkPDFUtils.h
index a9194f2e72a61798f98752102cbf25c13476f0ea..964689f4f2771c12bbc48634ebb0b9b2ebe2613e 100644
--- a/src/pdf/SkPDFUtils.h
+++ b/src/pdf/SkPDFUtils.h
@@ -12,6 +12,7 @@
 #include "SkPaint.h"
 #include "SkPath.h"
 #include "SkStream.h"
+#include "SkUtils.h"
 
 class SkMatrix;
 class SkPDFArray;
@@ -92,7 +93,15 @@ inline void WriteUInt8(SkDynamicMemoryWStream* wStream, uint8_t value) {
     result[1] = gHex[0xF & value];
     wStream->write(result, 2);
 }
-
+inline void WriteUTF16beHex(SkDynamicMemoryWStream* wStream, SkUnichar utf32) {
+    uint16_t utf16[2] = {0, 0};
+    size_t len = SkUTF16_FromUnichar(utf32, utf16);
+    SkASSERT(len == 1 || len == 2);
+    SkPDFUtils::WriteUInt16BE(wStream, utf16[0]);
+    if (len == 2) {
+        SkPDFUtils::WriteUInt16BE(wStream, utf16[1]);
+    }
+}
 }  // namespace SkPDFUtils
 
 #endif