Notify resource caches when pixelref genID goes stale

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 "SkResourceCache.h"
 #include "Test.h"
 
 namespace {
 static void* gGlobalAddress;
 struct TestingKey : public SkResourceCache::Key {
     intptr_t    fValue;
 
     TestingKey(intptr_t value) : fValue(value) {
-        this->init(&gGlobalAddress, sizeof(fValue));
+        this->init(&gGlobalAddress, 0, sizeof(fValue));
     }
 };
 struct TestingRec : public SkResourceCache::Rec {
     TestingRec(const TestingKey& key, uint32_t value) : fKey(key), fValue(value) {}
 
     TestingKey  fKey;
     intptr_t    fValue;
 
     const Key& getKey() const SK_OVERRIDE { return fKey; }
     size_t bytesUsed() const SK_OVERRIDE { return sizeof(fKey) + sizeof(fValue); }
@@ skipping 77 matching lines @@
     TestingKey key(1);
 
     cache.add(SkNEW_ARGS(TestingRec, (key, 2)));
     cache.add(SkNEW_ARGS(TestingRec, (key, 3)));
 
     // Lookup can return either value.
     intptr_t value = -1;
     REPORTER_ASSERT(r, cache.find(key, TestingRec::Visitor, &value));
     REPORTER_ASSERT(r, 2 == value || 3 == value);
 }