Update SkPicture cull rects with RTree information

src/core/SkPictureRecorder.cpp

Index: src/core/SkPictureRecorder.cpp
diff --git a/src/core/SkPictureRecorder.cpp b/src/core/SkPictureRecorder.cpp
index 42f8732c79032764cea607384538a64c93c0f505..1972ad3341678c008dd3fd2d1f4024f31b5edefa 100644
--- a/src/core/SkPictureRecorder.cpp
+++ b/src/core/SkPictureRecorder.cpp
@@ -60,6 +60,10 @@ SkPicture* SkPictureRecorder::endRecordingAsPicture() {
         } else {
             SkRecordFillBounds(fCullRect, *fRecord, fBBH.get());
         }
+        SkRect bbhBound = fBBH->getRootBound();
+        SkASSERT((bbhBound.isEmpty() || fCullRect.contains(bbhBound))
+            || (bbhBound.isEmpty() && fCullRect.isEmpty()));
+        fCullRect = bbhBound;
     }
 
     SkPicture* pict = SkNEW_ARGS(SkPicture, (fCullRect, fRecord, pictList, fBBH));