return and take SkImageGenerator as unique_ptr

BUG=skia:

Change-Id: I4bc11042dd1dbf1eabd40af206027bc65acc3186
Reviewed-on: https://skia-review.googlesource.com/8444
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Matt Sarett <msarett@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
diff --git a/tests/ImageTest.cpp b/tests/ImageTest.cpp
index 4f5f56f..d8a0633 100644
--- a/tests/ImageTest.cpp
+++ b/tests/ImageTest.cpp
@@ -17,6 +17,7 @@
 #include "SkImageGenerator.h"
 #include "SkImage_Base.h"
 #include "SkImagePriv.h"
+#include "SkMakeUnique.h"
 #include "SkPicture.h"
 #include "SkPictureRecorder.h"
 #include "SkPixelSerializer.h"
@@ -595,7 +596,8 @@
     REPORTER_ASSERT(reporter, nullptr == SkImage::MakeRasterCopy(pmap));
     REPORTER_ASSERT(reporter, nullptr == SkImage::MakeRasterData(info, nullptr, 0));
     REPORTER_ASSERT(reporter, nullptr == SkImage::MakeFromRaster(pmap, nullptr, nullptr));
-    REPORTER_ASSERT(reporter, nullptr == SkImage::MakeFromGenerator(new EmptyGenerator));
+    REPORTER_ASSERT(reporter, nullptr == SkImage::MakeFromGenerator(
+                                                            skstd::make_unique<EmptyGenerator>()));
 }
 
 DEF_TEST(ImageDataRef, reporter) {