Add scaled subset API to SkCodec

tests/CodexTest.cpp

Index: tests/CodexTest.cpp
diff --git a/tests/CodexTest.cpp b/tests/CodexTest.cpp
index 91fb6897b5875fb6d2db3c5fe636105c97a48b16..590e15cd29a6ff5f030f6d4d49d5bef82cd68dc9 100644
--- a/tests/CodexTest.cpp
+++ b/tests/CodexTest.cpp
@@ -239,7 +239,7 @@ static void check(skiatest::Reporter* r,
     for (int i = 0; i < 5; i++) {
         subset = generate_random_subset(&rand, size.width(), size.height());
         SkASSERT(!subset.isEmpty());
-        const bool supported = codec->getValidSubset(&subset);
+        const bool supported = codec->getScaledSubsetDimensions(1.0f, opts);
         REPORTER_ASSERT(r, supported == supportsSubsetDecoding);
 
         SkImageInfo subsetInfo = info.makeWH(subset.width(), subset.height());