Fix memory leak in nanobench

bench/SKPBench.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 "SKPBench.h"
 #include "SkCommandLineFlags.h"
 #include "SkMultiPictureDraw.h"
@@ skipping 55 matching lines @@
 }
 
 void SKPBench::onPerCanvasPostDraw(SkCanvas* canvas) {
     if (!fUseMultiPictureDraw) {
         return;
     }
 
     // Draw the last set of tiles into the master canvas in case we're
     // saving the images
     for (int i = 0; i < fTileRects.count(); ++i) {
-        canvas->drawImage(fSurfaces[i]->newImageSnapshot(),
+        SkAutoTUnref<SkImage> image(fSurfaces[i]->newImageSnapshot());
+        canvas->drawImage(image,
                           SkIntToScalar(fTileRects[i].fLeft), SkIntToScalar(fTileRects[i].fTop));
         SkSafeSetNull(fSurfaces[i]);
     }
 
     fSurfaces.rewind();
     fTileRects.rewind();
 }
 
 bool SKPBench::isSuitableFor(Backend backend) {
     return backend != kNonRendering_Backend;
@@ skipping 35 matching lines @@
                     canvas->clipRect(SkRect::Make(
                                 SkIRect::MakeXYWH(x, y, FLAGS_benchTile, FLAGS_benchTile)));
                     fPic->playback(canvas);
                 }
             }
 
             canvas->flush();
         }
     }
 }