Make SkPicture/SkImageGenerator default to SkCodec

tests/KtxTest.cpp

Index: tests/KtxTest.cpp
diff --git a/tests/KtxTest.cpp b/tests/KtxTest.cpp
index 84d162c0f83a103582b1e5d26384e4203f309dfa..99bae83329a7c802443217d107aa4dcf79b313fd 100644
--- a/tests/KtxTest.cpp
+++ b/tests/KtxTest.cpp
@@ -143,6 +143,9 @@ DEF_TEST(KtxReadUnpremul, reporter) {
     }
 }
 
+// For KtxReexportPKM, below. Defined in SkImageDecoder_ktx.cpp
+extern SkImageGenerator* decoder_image_generator(SkData*);
+
 /**
  * Finally, make sure that if we get ETC1 data from a PKM file that we can then
  * accurately write it out into a KTX file (i.e. transferring the ETC1 data from
@@ -160,7 +163,7 @@ DEF_TEST(KtxReexportPKM, reporter) {
     }
 
     bool installDiscardablePixelRefSuccess =
-        SkDEPRECATED_InstallDiscardablePixelRef(fileData, &etcBitmap);
+        SkDEPRECATED_InstallDiscardablePixelRef(decoder_image_generator(fileData), &etcBitmap);
     if (!installDiscardablePixelRefSuccess) {
         ERRORF(reporter, "failed to create discardable pixelRef from KTX file");
         return;