allow SkBitmapCache to operate on a local instance, for testability

src/core/SkResourceCache.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 "SkChecksum.h"
 #include "SkResourceCache.h"
 #include "SkMipMap.h"
@@ skipping 414 matching lines @@
 size_t SkResourceCache::GetTotalByteLimit() {
     SkAutoMutexAcquire am(gMutex);
     return get_cache()->getTotalByteLimit();
 }
 
 size_t SkResourceCache::SetTotalByteLimit(size_t newLimit) {
     SkAutoMutexAcquire am(gMutex);
     return get_cache()->setTotalByteLimit(newLimit);
 }
 
+SkResourceCache::DiscardableFactory SkResourceCache::GetDiscardableFactory() {
+    SkAutoMutexAcquire am(gMutex);
+    return get_cache()->discardableFactory();
+}
+
 SkBitmap::Allocator* SkResourceCache::GetAllocator() {
     SkAutoMutexAcquire am(gMutex);
     return get_cache()->allocator();
 }
 
 void SkResourceCache::Dump() {
     SkAutoMutexAcquire am(gMutex);
     get_cache()->dump();
 }
 
@@ skipping 43 matching lines @@
 }
 
 size_t SkGraphics::SetResourceCacheSingleAllocationByteLimit(size_t newLimit) {
     return SkResourceCache::SetSingleAllocationByteLimit(newLimit);
 }
 
 void SkGraphics::PurgeResourceCache() {
     return SkResourceCache::PurgeAll();
 }