GM: showmiplevels handles bitmap memory in a nicer way.

gm/downsamplebitmap.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 
 #include "Resources.h"
@@ skipping 174 matching lines @@
               fBM.allocN32Pixels(1, 1);
               *(fBM.getAddr32(0,0)) = 0xFF0000FF; // red == bad
           }
           fSize = fBM.height();
       }
   private:
       typedef DownsampleBitmapGM INHERITED;
 };
 
 #include "SkMipMap.h"
+
+static void release_mipmap(void*, void* context) {
+    ((SkMipMap*)context)->unref();
+}
+
 class ShowMipLevels : public skiagm::GM {
 public:
     SkBitmap    fBM;
 
     ShowMipLevels() {
         this->setBGColor(0xFFDDDDDD);
         make_checker(&fBM, 512, 256);
     }
 
 protected:
@@ skipping 12 matching lines @@
         canvas->drawBitmap(fBM, x, y, NULL);
         y += fBM.height() + 4;
 
         SkAutoTUnref<SkMipMap> mm(SkMipMap::Build(fBM, NULL));
 
         SkMipMap::Level level;
         SkScalar scale = 0.5f;
         while (mm->extractLevel(scale, &level)) {
             SkImageInfo info = SkImageInfo::MakeN32Premul(level.fWidth, level.fHeight);
             SkBitmap bm;
-            bm.installPixels(info, level.fPixels, level.fRowBytes);
+            bm.installPixels(info, level.fPixels, level.fRowBytes, NULL,
+                             &release_mipmap, (void*)(SkRef(mm.get())));
+            bm.setImmutable();
             canvas->drawBitmap(bm, x, y, NULL);
             y += bm.height() + 4;
             scale /= 2;
             if (info.width() == 1 || info.height() == 1) {
                 break;
             }
         }
     }
 
 private:
@@ skipping 19 matching lines @@
 DEF_GM( return new DownsampleBitmapCheckerboardGM(512,256, SkPaint::kLow_FilterLevel); )
 DEF_GM( return new DownsampleBitmapImageGM("mandrill_512.png", SkPaint::kLow_FilterLevel); )
 DEF_GM( return new DownsampleBitmapImageGM("mandrill_132x132_12x12.astc",
                                            SkPaint::kLow_FilterLevel); )
 
 DEF_GM( return new DownsampleBitmapTextGM(72, SkPaint::kNone_FilterLevel); )
 DEF_GM( return new DownsampleBitmapCheckerboardGM(512,256, SkPaint::kNone_FilterLevel); )
 DEF_GM( return new DownsampleBitmapImageGM("mandrill_512.png", SkPaint::kNone_FilterLevel); )
 DEF_GM( return new DownsampleBitmapImageGM("mandrill_132x132_12x12.astc",
                                            SkPaint::kNone_FilterLevel); )