add drawPicture variant that takes a matrix and paint

will need some staging strategy, since chrome and blink have overrides of onDrawPicture

R=robertphillips@google.com, fmalita@google.com, bsalomon@google.com, mtklein@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/448793004
diff --git a/src/utils/SkNWayCanvas.cpp b/src/utils/SkNWayCanvas.cpp
index b33c99e..d02835a 100644
--- a/src/utils/SkNWayCanvas.cpp
+++ b/src/utils/SkNWayCanvas.cpp
@@ -265,10 +265,11 @@
     }
 }
 
-void SkNWayCanvas::onDrawPicture(const SkPicture* picture) {
+void SkNWayCanvas::onDrawPicture(const SkPicture* picture, const SkMatrix* matrix,
+                                 const SkPaint* paint) {
     Iter iter(fList);
     while (iter.next()) {
-        iter->drawPicture(picture);
+        iter->drawPicture(picture, matrix, paint);
     }
 }