SkPaintFilterCanvas should inherit the target canvas state

include/utils/SkPaintFilterCanvas.h

Index: include/utils/SkPaintFilterCanvas.h
diff --git a/include/utils/SkPaintFilterCanvas.h b/include/utils/SkPaintFilterCanvas.h
index da0333e7e67f60e6802491b5e8636ed3a505b041..d693758797ce624f29c5c613c672482d486fd74e 100644
--- a/include/utils/SkPaintFilterCanvas.h
+++ b/include/utils/SkPaintFilterCanvas.h
@@ -16,8 +16,17 @@
 */
 class SK_API SkPaintFilterCanvas : public SkNWayCanvas {
 public:
+    /**
+     * DEPRECATED: use the variant below.
+     */
     SkPaintFilterCanvas(int width, int height);
 
+    /**
+     * The new SkPaintFilterCanvas is configured for forwarding to the
+     * specified canvas.  Also copies the target canvas matrix and clip bounds.
+     */
+    SkPaintFilterCanvas(SkCanvas* canvas);
+
     enum Type {
         kPaint_Type,
         kPoint_Type,