Destroy SkScanlineDecoder in the SkCodec subclass destructors

include/codec/SkCodec.h

Index: include/codec/SkCodec.h
diff --git a/include/codec/SkCodec.h b/include/codec/SkCodec.h
index 2e47a261f3924f2b018d988af56440f4310de2d3..e462be2e7d64c494de89cc03241da7c5de4c08d9 100644
--- a/include/codec/SkCodec.h
+++ b/include/codec/SkCodec.h
@@ -168,15 +168,32 @@ protected:
      */
     RewindState SK_WARN_UNUSED_RESULT rewindIfNeeded();
 
-    /*
-     *
+    /**
      * Get method for the input stream
-     *
      */
     SkStream* stream() {
         return fStream.get();
     }
 
+    /**
+     * If the codec has a scanline decoder, return it (no ownership change occurs)
+     * else return NULL.
+     * The returned decoder is valid while the codec exists and the client has not
+     * created a new scanline decoder.
+     */
+    SkScanlineDecoder* scanlineDecoder() {
+        return fScanlineDecoder.get();
+    }
+
+    /**
+     * Allow the codec subclass to detach and take ownership of the scanline decoder.
+     * This will likely be used when the scanline decoder needs to be destroyed
+     * in the destructor of the subclass.
+     */
+    SkScanlineDecoder* detachScanlineDecoder() {
+        return fScanlineDecoder.detach();
+    }
+
 private:
     SkAutoTDelete<SkStream>             fStream;
     bool                                fNeedsRewind;