SkDiscardableMemoryPool to abstract class

tests/ImageCacheTest.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 "SkDiscardableMemory.h"
 #include "SkScaledImageCache.h"
 #include "Test.h"
@@ skipping 63 matching lines @@
         }
     }
 
     cache.setByteLimit(0);
 }
 
 #include "SkDiscardableMemoryPool.h"
 
 static SkDiscardableMemoryPool* gPool;
 static SkDiscardableMemory* pool_factory(size_t bytes) {
+    SkASSERT(gPool);
     return gPool->create(bytes);
 }
 
 DEF_TEST(ImageCache, reporter) {
     static const size_t defLimit = DIM * DIM * 4 * COUNT + 1024;    // 1K slop
 
     {
         SkScaledImageCache cache(defLimit);
         test_cache(reporter, cache, true);
     }
     {
-        SkDiscardableMemoryPool pool(defLimit);
-        gPool = &pool;
+        SkAutoTUnref<SkDiscardableMemoryPool> pool(
+                SkDiscardableMemoryPool::Create(defLimit, NULL));
+        gPool = pool.get();
         SkScaledImageCache cache(pool_factory);
         test_cache(reporter, cache, true);
     }
     {
         SkScaledImageCache cache(SkDiscardableMemory::Create);
         test_cache(reporter, cache, false);
     }
 }
 
 DEF_TEST(ImageCache_doubleAdd, r) {
@@ skipping 15 matching lines @@
     cache.unlock(id1);
     cache.unlock(id2);
 
     SkBitmap tmp;
     // Lookup should return the value that was added last.
     SkScaledImageCache::ID* id = cache.findAndLock(original, 0.5f, 0.5f, &tmp);
     REPORTER_ASSERT(r, NULL != id);
     REPORTER_ASSERT(r, tmp.getGenerationID() == scaled2.getGenerationID());
     cache.unlock(id);
 }