Add SkCachedData and use it for SkMipMap

src/core/SkMaskCache.h

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkMaskCache_DEFINED
+#define SkMaskCache_DEFINED
+
+#include "SkScalar.h"
+#include "SkMask.h"
+
+class SkCachedData;
+class SkDiscardableMemory;
+struct SkMask;
+class SkResourceCache;
+class SkRRect;
+
+class SkMaskCache {
+public:
+    static SkCachedData* NewCachedData(size_t size, SkResourceCache* localCache = NULL);
+
+    /**
+     *  If a matching mask/pixel-data is found for the specified key, lock the pixel-data and
+     *  return the mask and pixel-data. In the case the caller MUST call unlock() on the pixel-data
+     *  when they are done using it, after which the pixel-data object will no longer be valid.
+     *
+     *  If NULL is returned, the mask parameter is ignored.
+     */
+    static SkCachedData* FindAndLock(SkScalar sigma, const SkRect&,
+                                           SkMask* result, SkResourceCache* localCache = NULL);
+    static SkCachedData* FindAndLock(SkScalar sigma, const SkRect& r0, const SkRect& r1,
+                                           SkMask* result, SkResourceCache* localCache = NULL);
+    static SkCachedData* FindAndLock(SkScalar sigma, const SkRRect&,
+                                           SkMask* result, SkResourceCache* localCache = NULL);
+
+    /**
+     *  Add a mask and its pixel-data to the cache. The pixel-data MUST be locked.
+     *  Ownership of the pixel-data is transfered to the cache, so the caller must not reference
+     *  it after this call.
+     */
+    static void Add(SkScalar sigma, const SkRect&,
+                    const SkMask& result, SkCachedData* data, SkResourceCache* localCache = NULL);
+    static void Add(SkScalar sigma, const SkRect& r0, const SkRect& r1,
+                    const SkMask& result, SkCachedData* data, SkResourceCache* localCache = NULL);
+    static void Add(SkScalar sigma, const SkRRect&,
+                    const SkMask& result, SkCachedData* data, SkResourceCache* localCache = NULL);
+};
+
+#endif