Add an SkImageGeneratorCG

dm/DMSrcSink.h

Index: dm/DMSrcSink.h
diff --git a/dm/DMSrcSink.h b/dm/DMSrcSink.h
index 3190576c680d4936e3e46cf8c5965ad3c7ae0f08..c1cdfd81cd31f7045982c88b50b6afc3aa31a4f1 100644
--- a/dm/DMSrcSink.h
+++ b/dm/DMSrcSink.h
@@ -112,7 +112,6 @@ public:
         kStripe_Mode, // Tests the skipping of scanlines
         kCroppedScanline_Mode, // Tests (jpeg) cropped scanline optimization
         kSubset_Mode, // For codecs that support subsets directly.
-        kGen_Mode,    // Test SkCodecImageGenerator (includes YUV)
     };
     enum DstColorType {
         kGetFromCanvas_DstColorType,
@@ -187,6 +186,25 @@ private:
     uint32_t                                 fSampleSize;
 };
 
+class ImageGenSrc : public Src {
+public:
+    enum Mode {
+        kCodec_Mode, // Use CodecImageGenerator
+        kCG_Mode,    // Use CG
+    };
+    ImageGenSrc(Path, Mode);
+
+    Error draw(SkCanvas*) const override;
+    SkISize size() const override;
+    Name name() const override;
+    bool veto(SinkFlags) const override;
+    bool serial() const override { return fRunSerially; }
+private:
+    Path fPath;
+    Mode fMode;
+    bool fRunSerially;
+};
+
 class SKPSrc : public Src {
 public:
     explicit SKPSrc(Path path);