add SkDrawPictureCallback optional parameter to drawPicture(), which can abort the picture drawing.

src/core/SkCanvas.cpp

Index: src/core/SkCanvas.cpp
diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index df2a0f9e879b27b3167e4138bc95d78626f2f1b3..0613b4ed8e8a4601847b8f44b07befc8dc9914be 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -2131,8 +2131,8 @@ void SkCanvas::drawTextOnPathHV(const void* text, size_t byteLength,
 
 ///////////////////////////////////////////////////////////////////////////////
 
-void SkCanvas::drawPicture(SkPicture& picture) {
-    picture.draw(this);
+void SkCanvas::drawPicture(SkPicture& pict, SkDrawPictureCallback* callback) {
+    pict.draw(this, callback);
 }
 
 ///////////////////////////////////////////////////////////////////////////////