calculate cull rects for SkMiniPictures

This is the other half of https://skia-review.googlesource.com/c/7874/,
adding the cull-shrinking feature of SkBigPictures to SkMiniPictures.

Like SkBigPictures, shrink only when we're asked to build an R-tree.
(We don't actually build a tree for one rect, of course.)

We could do unconditionally, but SkPictureImageFilter uses the cull rect
as its crop.  It's unclear to me what this image filter unit test I've
changed here was intending... had it had two draws we would have shrunk
its cull, but because it was hitting the 1-draw SkMiniPicture path it
kept the larger user-supplied cull.

As the test doesn't appear to have been written with cull shrinking in
mind, I've removed its SkRTreeFactory to keep that feature explicitly
disabled there.

BUG=skia:5974

Change-Id: I4118d2e85f2a69adef2e7a7fa9b9b8c17607a94f
Reviewed-on: https://skia-review.googlesource.com/12624
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/include/private/SkMiniRecorder.h b/include/private/SkMiniRecorder.h
index 06b35ca714..fd1e8f624d 100644
--- a/include/private/SkMiniRecorder.h
+++ b/include/private/SkMiniRecorder.h
@@ -25,11 +25,12 @@ public:
     bool drawTextBlob(const SkTextBlob*, SkScalar x, SkScalar y, const SkPaint&);
 
     // Detach anything we've recorded as a picture, resetting this SkMiniRecorder.
-    sk_sp<SkPicture> detachAsPicture(const SkRect& cull);
+    // If cull is nullptr we'll calculate it.
+    sk_sp<SkPicture> detachAsPicture(const SkRect* cull);
 
     // Flush anything we've recorded to the canvas, resetting this SkMiniRecorder.
     // This is logically the same as but rather more efficient than:
-    //    sk_sp<SkPicture> pic(this->detachAsPicture(SkRect::MakeEmpty()));
+    //    sk_sp<SkPicture> pic(this->detachAsPicture(nullptr));
     //    pic->playback(canvas);
     void flushAndReset(SkCanvas*);