Fix layer hoisting image filter corner cases

src/core/SkLayerInfo.h

Index: src/core/SkLayerInfo.h
diff --git a/src/core/SkLayerInfo.h b/src/core/SkLayerInfo.h
index add57d780c6ea0bed6478c6543a3b22bb0c6fcd0..a47c3f1199c52fdd5682bf91a7dbe72b3da2b87e 100644
--- a/src/core/SkLayerInfo.h
+++ b/src/core/SkLayerInfo.h
@@ -28,6 +28,9 @@ public:
         const SkPicture* fPicture;
         // The device space bounds of this layer.
         SkRect fBounds;
+        // If not-empty, the optional bounds parameter passed in to the saveLayer
+        // call.
+        SkRect fSrcBounds;
         // The pre-matrix begins as the identity and accumulates the transforms
         // of the containing SkPictures (if any). This matrix state has to be
         // part of the initial matrix during replay so that it will be