discardable pixelrefs are gone, update tests accordingly

tests/JpegTest.cpp

Index: tests/JpegTest.cpp
diff --git a/tests/JpegTest.cpp b/tests/JpegTest.cpp
index daa932c4c9b046f2a1b89da1578d3d357923e190..d61b0bd3111cd89f62930c3ed9cff2d81b3abea9 100644
--- a/tests/JpegTest.cpp
+++ b/tests/JpegTest.cpp
@@ -457,22 +457,16 @@ DEF_TEST(Jpeg, reporter) {
 DEF_TEST(Jpeg_YUV, reporter) {
     size_t len = sizeof(goodJpegImage);
     SkMemoryStream* stream = new SkMemoryStream(goodJpegImage, len);
-
-    SkBitmap bitmap;
     SkDecodingImageGenerator::Options opts;
-    bool pixelsInstalled = SkInstallDiscardablePixelRef(
-                SkDecodingImageGenerator::Create(stream, opts), &bitmap);
-    REPORTER_ASSERT(reporter, pixelsInstalled);
-
-    if (!pixelsInstalled) {
+    SkAutoTDelete<SkImageGenerator> gen(SkDecodingImageGenerator::Create(stream, opts));
+    REPORTER_ASSERT(reporter, gen);
+    if (!gen) {
         return;
     }
 
-    SkPixelRef* pixelRef = bitmap.pixelRef();
     SkISize yuvSizes[3];
-    bool sizesComputed = (nullptr != pixelRef) && pixelRef->getYUV8Planes(yuvSizes, nullptr, nullptr, nullptr);
+    bool sizesComputed = gen->getYUV8Planes(yuvSizes, nullptr, nullptr, nullptr);
     REPORTER_ASSERT(reporter, sizesComputed);
-
     if (!sizesComputed) {
         return;
     }
@@ -495,5 +489,5 @@ DEF_TEST(Jpeg_YUV, reporter) {
     planes[2] = (uint8_t*)planes[1] + sizes[1];
 
     // Get the YUV planes
-    REPORTER_ASSERT(reporter, pixelRef->getYUV8Planes(yuvSizes, planes, rowBytes, nullptr));
+    REPORTER_ASSERT(reporter, gen->getYUV8Planes(yuvSizes, planes, rowBytes, nullptr));
 }