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

src/core/SkPicture.cpp

Index: src/core/SkPicture.cpp
diff --git a/src/core/SkPicture.cpp b/src/core/SkPicture.cpp
index 1ff58656512681ed5ac056d1399f9558c33f0c91..ab2faea6b6b4eb38b6e0a9a9ac4ae5338cb46c8b 100644
--- a/src/core/SkPicture.cpp
+++ b/src/core/SkPicture.cpp
@@ -253,10 +253,10 @@ void SkPicture::endRecording() {
     SkASSERT(NULL == fRecord);
 }
 
-void SkPicture::draw(SkCanvas* surface) {
+void SkPicture::draw(SkCanvas* surface, SkDrawPictureCallback* callback) {
     this->endRecording();
     if (fPlayback) {
-        fPlayback->draw(*surface);
+        fPlayback->draw(*surface, callback);
     }
 }