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/SkProxyCanvas.cpp b/src/utils/SkProxyCanvas.cpp
index 1029f40..773fd20 100644
--- a/src/utils/SkProxyCanvas.cpp
+++ b/src/utils/SkProxyCanvas.cpp
@@ -136,8 +136,9 @@
     fProxy->drawTextOnPath(text, byteLength, path, matrix, paint);
 }
 
-void SkProxyCanvas::onDrawPicture(const SkPicture* picture) {
-    fProxy->drawPicture(picture);
+void SkProxyCanvas::onDrawPicture(const SkPicture* picture, const SkMatrix* matrix,
+                                  const SkPaint* paint) {
+    fProxy->drawPicture(picture, matrix, paint);
 }
 
 void SkProxyCanvas::drawVertices(VertexMode vmode, int vertexCount,