assert that non-empty clips have non-empty bounds

src/core/SkAAClip.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAAClip.h"
 #include "SkAtomics.h"
 #include "SkBlitter.h"
@@ skipping 173 matching lines @@
     }
     SkASSERT(0 == width);
     return row - origRow;
 }
 
 void SkAAClip::validate() const {
     if (nullptr == fRunHead) {
         SkASSERT(fBounds.isEmpty());
         return;
     }
+    SkASSERT(!fBounds.isEmpty());
 
     const RunHead* head = fRunHead;
     SkASSERT(head->fRefCnt > 0);
     SkASSERT(head->fRowCount > 0);
 
     const YOffset* yoff = head->yoffsets();
     const YOffset* ystop = yoff + head->fRowCount;
     const int lastY = fBounds.height() - 1;
 
     // Y and offset must be monotonic
@@ skipping 2006 matching lines @@
             rowMask.fBounds.fBottom = y + 1;
             fBlitter->blitMask(rowMask, rowMask.fBounds);
             src = (const void*)((const char*)src + srcRB);
         } while (++y < localStopY);
     } while (y < stopY);
 }
 
 const SkPixmap* SkAAClipBlitter::justAnOpaqueColor(uint32_t* value) {
     return nullptr;
 }