Do not call blitAntiRect for empty rect

src/core/SkScan_AAAPath.cpp

 /*
  * Copyright 2016 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAntiRun.h"
 #include "SkBlitter.h"
 #include "SkEdge.h"
@@ skipping 979 matching lines @@
                     if (partialRite > 0) {
                         blitter->blitAntiH(fullRite, fullTop - 1,
                                 f2a(SkFixedMul_lowprec(partialTop, partialRite)));
                     }
                     if (forceRLE) {
                         ((RunBasedAdditiveBlitter*)blitter)->flush_if_y_changed(y, y + partialTop);
                     }
                 }
 
                 // Blit all full-height rows from fullTop to fullBot
-                if (fullBot > fullTop) {
+                if (fullBot > fullTop &&
+                        // SkAAClip cannot handle the empty rect so check the non-emptiness here
+                        // (bug chromium:662800)
+                        (fullRite > fullLeft || f2a(partialLeft) > 0 || f2a(partialRite) > 0)) {
                     blitter->getRealBlitter()->blitAntiRect(fullLeft - 1, fullTop,
                                                             fullRite - fullLeft, fullBot - fullTop,
                                                             f2a(partialLeft), f2a(partialRite));
                 }
 
                 if (partialBot > 0) { // blit last partial row
                     if (partialLeft > 0) {
                         blitter->blitAntiH(fullLeft - 1, fullBot,
                                            f2a(SkFixedMul_lowprec(partialBot, partialLeft)));
                     }
@@ skipping 330 matching lines @@
         AAAFillPath(path, clip.bwRgn(), blitter);
     } else {
         SkRegion        tmp;
         SkAAClipBlitter aaBlitter;
 
         tmp.setRect(clip.getBounds());
         aaBlitter.init(blitter, &clip.aaRgn());
         AAAFillPath(path, tmp, &aaBlitter, true);
     }
 }