move ashmem switching logic to SkDiscardableMemory::Create

tests/ImageDecodingTest.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 "SkBitmap.h"
 #include "SkCanvas.h"
 #include "SkColor.h"
@@ skipping 473 matching lines @@
 // example of how Android will do this inside their BitmapFactory
 static SkPixelRef* install_pixel_ref(SkBitmap* bitmap,
                                      SkStreamRewindable* stream,
                                      int sampleSize, bool ditherImage) {
     SkASSERT(bitmap != NULL);
     SkASSERT(stream != NULL);
     SkASSERT(stream->rewind());
     SkASSERT(stream->unique());
     SkColorType colorType = bitmap->colorType();
     SkDecodingImageGenerator::Options opts(sampleSize, ditherImage, colorType);
-    SkAutoTDelete<SkImageGenerator> gen(
-        SkDecodingImageGenerator::Create(stream, opts));
-    SkImageInfo info;
-    if ((NULL == gen.get()) || !gen->getInfo(&info)) {
-        return NULL;
-    }
-    SkDiscardableMemory::Factory* factory = NULL;
-    if (info.getSafeSize(info.minRowBytes()) < (32 * 1024)) {
-        // only use ashmem for large images, since mmaps come at a price
-        factory = SkGetGlobalDiscardableMemoryPool();
-    }
-    if (SkInstallDiscardablePixelRef(gen.detach(), bitmap, factory)) {
+    if (SkInstallDiscardablePixelRef(
+                SkDecodingImageGenerator::Create(stream, opts), bitmap)) {
         return bitmap->pixelRef();
     }
     return NULL;
 }
 /**
  *  A test for the SkDecodingImageGenerator::Create and
  *  SkInstallDiscardablePixelRef functions.
  */
 DEF_TEST(ImprovedBitmapFactory, reporter) {
     SkString resourcePath = skiatest::Test::GetResourcePath();
@@ skipping 214 matching lines @@
                     }
                     SkDecodingImageGenerator::Options options(scaleList[i],
                                                               ditherList[j]);
                     test_options(reporter, options, encodedStream, encodedData,
                                  useDataList[m], path);
                 }
             }
         }
     }
 }