add ImageGenerator::NewFromData to porting layer

tests/CachedDecodingPixelRefTest.cpp

Index: tests/CachedDecodingPixelRefTest.cpp
diff --git a/tests/CachedDecodingPixelRefTest.cpp b/tests/CachedDecodingPixelRefTest.cpp
index b3eb5327d91291fe001aab9cef1e09889f0fdfa1..48100e714b3337fc33bd5d9c94b62e14f4e596de 100644
--- a/tests/CachedDecodingPixelRefTest.cpp
+++ b/tests/CachedDecodingPixelRefTest.cpp
@@ -9,7 +9,6 @@
 #include "SkCachingPixelRef.h"
 #include "SkCanvas.h"
 #include "SkData.h"
-#include "SkDecodingImageGenerator.h"
 #include "SkDiscardableMemoryPool.h"
 #include "SkImageDecoder.h"
 #include "SkImageGeneratorPriv.h"
@@ -143,15 +142,11 @@ static void test_three_encodings(skiatest::Reporter* reporter,
 
 ////////////////////////////////////////////////////////////////////////////////
 static bool install_skCachingPixelRef(SkData* encoded, SkBitmap* dst) {
-    return SkCachingPixelRef::Install(
-        SkDecodingImageGenerator::Create(
-            encoded, SkDecodingImageGenerator::Options()), dst);
+    return SkCachingPixelRef::Install(SkImageGenerator::NewFromData(encoded), dst);
 }
 static bool install_skDiscardablePixelRef(SkData* encoded, SkBitmap* dst) {
     // Use system-default discardable memory.
-    return SkInstallDiscardablePixelRef(
-        SkDecodingImageGenerator::Create(
-            encoded, SkDecodingImageGenerator::Options()), dst);
+    return SkInstallDiscardablePixelRef(encoded, dst);
 }
 
 ////////////////////////////////////////////////////////////////////////////////