Fix saveLayer() with a pixel-moving filter vs SkBBoxHierarchyRecord / SkRecordDraw

src/core/SkRecordDraw.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkRecordDraw.h"
 #include "SkTSort.h"
 
@@ skipping 171 matching lines @@
     // TODO: remove this trivially-safe default when done bounding all ops
     template <typename T> SkIRect bounds(const T&) { return SkIRect::MakeLargest(); }
 
     void pushSaveBlock() {
         // Starting a new Save block.  Push a new entry to represent that.
         SaveBounds sb = { 0, SkIRect::MakeEmpty() };
         fSaveStack.push(sb);
         this->pushControl();
     }
 
+    static bool PaintMayAffectTransparentBlack(const SkPaint* paint) {
+        // FIXME: this is very conservative
+        return paint && (paint->getImageFilter() || paint->getColorFilter());
+    }
+
     SkIRect popSaveBlock() {
         // We're done the Save block.  Apply the block's bounds to all control ops inside it.
         SaveBounds sb;
         fSaveStack.pop(&sb);
+
+        // If the paint affects transparent black, we can't trust any of our calculated bounds.
+        const SkIRect& bounds =
+            PaintMayAffectTransparentBlack(sb.paint) ? fCurrentClipBounds : sb.bounds;
+
         while (sb.controlOps --> 0) {
-            this->popControl(sb.bounds);
+            this->popControl(bounds);
         }
 
         // This whole Save block may be part another Save block.
-        this->updateSaveBounds(sb.bounds);
+        this->updateSaveBounds(bounds);
 
         // If called from a real Restore (not a phony one for balance), it'll need the bounds.
-        return sb.bounds;
+        return bounds;
     }
 
     void pushControl() {
         fControlIndices.push(fCurrentOp);
         if (!fSaveStack.isEmpty()) {
             fSaveStack.top().controlOps++;
         }
     }
 
     void popControl(const SkIRect& bounds) {
@@ skipping 15 matching lines @@
     unsigned fCurrentOp;
     SkTDArray<SaveBounds> fSaveStack;
     SkTDArray<unsigned>   fControlIndices;
 };
 
 }  // namespace SkRecords
 
 void SkRecordFillBounds(const SkRecord& record, SkBBoxHierarchy* bbh) {
     SkRecords::FillBounds(record, bbh);
 }