Add SkCachedData and use it for SkMipMap

tests/SkResourceCacheTest.cpp

Index: tests/SkResourceCacheTest.cpp
diff --git a/tests/SkResourceCacheTest.cpp b/tests/SkResourceCacheTest.cpp
index f13476a5a3b681056b07aae7e9923250c92327f1..0e941758eede8bce9de3d51d53376eb9b398c3e7 100644
--- a/tests/SkResourceCacheTest.cpp
+++ b/tests/SkResourceCacheTest.cpp
@@ -121,6 +121,55 @@ DEF_TEST(BitmapCache_add_rect, reporter) {
     REPORTER_ASSERT(reporter, SkBitmapCache::Find(cachedBitmap.getGenerationID(), rect, &bm, cache));
 }
 
+#include "SkMipMap.h"
+
+enum LockedState {
+    kNotLocked,
+    kLocked,
+};
+
+enum CachedState {
+    kNotInCache,
+    kInCache,
+};
+
+static void check_data(skiatest::Reporter* reporter, const SkCachedData* data,
+                       int refcnt, CachedState cacheState, LockedState lockedState) {
+    REPORTER_ASSERT(reporter, data->testing_only_getRefCnt() == refcnt);
+    REPORTER_ASSERT(reporter, data->testing_only_isInCache() == (kInCache == cacheState));
+    bool isLocked = (data->data() != NULL);
+    REPORTER_ASSERT(reporter, isLocked == (lockedState == kLocked));
+}
+
+static void test_mipmapcache(skiatest::Reporter* reporter, SkResourceCache* cache) {
+    cache->purgeAll();
+
+    SkBitmap src;
+    src.allocN32Pixels(5, 5);
+    src.setImmutable();
+
+    const SkMipMap* mipmap = SkMipMapCache::FindAndRef(src, cache);
+    REPORTER_ASSERT(reporter, NULL == mipmap);
+
+    mipmap = SkMipMapCache::AddAndRef(src, cache);
+    REPORTER_ASSERT(reporter, mipmap);
+    check_data(reporter, mipmap, 2, kInCache, kLocked);
+
+    mipmap->unref();
+    // tricky, since technically after this I'm no longer an owner, but since the cache is
+    // local, I know it won't get purged behind my back
+    check_data(reporter, mipmap, 1, kInCache, kNotLocked);
+
+    // find us again
+    mipmap = SkMipMapCache::FindAndRef(src, cache);
+    check_data(reporter, mipmap, 2, kInCache, kLocked);
+
+    cache->purgeAll();
+    check_data(reporter, mipmap, 1, kNotInCache, kLocked);
+
+    mipmap->unref();
+}
+
 DEF_TEST(BitmapCache_discarded_bitmap, reporter) {
     SkResourceCache::DiscardableFactory factory = SkResourceCache::GetDiscardableFactory();
     SkBitmap::Allocator* allocator = SkBitmapCache::GetAllocator();
@@ -165,4 +214,6 @@ DEF_TEST(BitmapCache_discarded_bitmap, reporter) {
     // We can add the bitmap back to the cache and find it again.
     REPORTER_ASSERT(reporter, SkBitmapCache::Add(cachedBitmap.getGenerationID(), rect, cachedBitmap, cache));
     REPORTER_ASSERT(reporter, SkBitmapCache::Find(cachedBitmap.getGenerationID(), rect, &bm, cache));
+
+    test_mipmapcache(reporter, cache);
 }