Add an SkImageGeneratorCG

src/ports/SkImageGeneratorCG.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkTypes.h"
+#if defined(SK_BUILD_FOR_MAC) || defined(SK_BUILD_FOR_IOS)
+
+#include "SkCGUtils.h"
+#include "SkData.h"
+#include "SkImageGenerator.h"
+#include "SkTemplates.h"
+
+class SkImageGeneratorCG : public SkImageGenerator {
+public:
+    /*
+     * Refs the data if an image generator can be returned.  Otherwise does
+     * not affect the data.
+     */
+    static SkImageGenerator* NewFromEncodedCG(SkData* data);
+
+protected:
+    SkData* onRefEncodedData(SK_REFENCODEDDATA_CTXPARAM) override;
+
+    bool onGetPixels(const SkImageInfo& info, void* pixels, size_t rowBytes, SkPMColor ctable[],
+            int* ctableCount) override;
+
+private:
+    /*
+     * Takes ownership of the imageSrc
+     * Refs the data
+     */
+    SkImageGeneratorCG(const SkImageInfo& info, const void* imageSrc, SkData* data);
+
+    SkAutoTCallVProc<const void, CFRelease> fImageSrc;
+    SkAutoTUnref<SkData>                    fData;
+    
+    typedef SkImageGenerator INHERITED;
+};
+
+#endif //defined(SK_BUILD_FOR_MAC) || defined(SK_BUILD_FOR_IOS)