SkPdf: smaller color serialization

tests/PDFPrimitivesTest.cpp

Index: tests/PDFPrimitivesTest.cpp
diff --git a/tests/PDFPrimitivesTest.cpp b/tests/PDFPrimitivesTest.cpp
index 9e2a89e60953b067faf69e588a05bad9b6a07657..d816b60823010b3fbc76187306fd2f2b155b6b73 100644
--- a/tests/PDFPrimitivesTest.cpp
+++ b/tests/PDFPrimitivesTest.cpp
@@ -491,3 +491,16 @@ DEF_TEST(PDFPrimitives_Scalar, reporter) {
         check_pdf_scalar_serialization(reporter, inputFloat);
     }
 }
+
+// Test SkPDFUtils:: for accuracy.
+DEF_TEST(PDFPrimitives_Color, reporter) {
+    char buffer[5];
+    for (int i = 0; i < 256; ++i) {
+        size_t len = SkPDFUtils::ColorToDecimal(i, buffer);
+        REPORTER_ASSERT(reporter, len == strlen(buffer));
+        float f;
+        REPORTER_ASSERT(reporter, 1 == sscanf(buffer, "%f", &f));
+        int roundTrip = (int)(0.5 + f * 255);
+        REPORTER_ASSERT(reporter, roundTrip == i);
+    }
+}