Add subsetting to SkScaledCodec

tools/SkBitmapRegionDecoderInterface.h

Index: tools/SkBitmapRegionDecoderInterface.h
diff --git a/tools/SkBitmapRegionDecoderInterface.h b/tools/SkBitmapRegionDecoderInterface.h
index bc28c2b2af6f2710c8c2d94ef3a64abb45cbe2c2..e4a3744d67d67dbda791592c52229d98dfd3b8aa 100644
--- a/tools/SkBitmapRegionDecoderInterface.h
+++ b/tools/SkBitmapRegionDecoderInterface.h
@@ -21,7 +21,7 @@ public:
     enum Strategy {
         kCanvas_Strategy,   // Draw to the canvas, uses SkCodec
         kOriginal_Strategy, // Sampling, uses SkImageDecoder
-        // TODO (msarett): Add strategy for SkScaledCodec
+        kCodec_Strategy,    // Uses SkScaledCodec for scaling and subsetting
     };
 
     /*
@@ -57,6 +57,12 @@ public:
                                    int height, int sampleSize,
                                    SkColorType colorType) = 0;
 
+    /*
+     * @param  Requested destination color type
+     * @return true if we support the requested color type and false otherwise
+     */
+    virtual bool conversionSupported(SkColorType colorType) = 0;
+
     int width() const { return fWidth; }
     int height() const { return fHeight; }