private iterator to visit all resource cache entries

bench/ImageCacheBench.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 "Benchmark.h"
 #include "SkResourceCache.h"
 
 namespace {
 static void* gGlobalAddress;
 class TestKey : public SkResourceCache::Key {
 public:
     intptr_t fValue;
 
     TestKey(intptr_t value) : fValue(value) {
         this->init(&gGlobalAddress, 0, sizeof(fValue));
     }
 };
 struct TestRec : public SkResourceCache::Rec {
     TestKey     fKey;
     intptr_t    fValue;
 
     TestRec(const TestKey& key, intptr_t value) : fKey(key), fValue(value) {}
 
     const Key& getKey() const override { return fKey; }
     size_t bytesUsed() const override { return sizeof(fKey) + sizeof(fValue); }
+    const char* getCategory() const override { return "imagecachebench-test"; }
+    SkDiscardableMemory* diagnostic_only_getDiscardable() const override { return NULL; }
 
     static bool Visitor(const SkResourceCache::Rec&, void*) {
         return true;
     }
 };
 }
 
 class ImageCacheBench : public Benchmark {
     SkResourceCache fCache;
 
@@ skipping 27 matching lines @@
         }
     }
 
 private:
     typedef Benchmark INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 DEF_BENCH( return new ImageCacheBench(); )