Add subsetting to SkScaledCodec

src/codec/SkCodec_wbmp.h

Index: src/codec/SkCodec_wbmp.h
diff --git a/src/codec/SkCodec_wbmp.h b/src/codec/SkCodec_wbmp.h
index 84187a6def2d4d1876790a954c517cc1804da848..eaaf7083da370ad862916903c1aa3927c80f93cd 100644
--- a/src/codec/SkCodec_wbmp.h
+++ b/src/codec/SkCodec_wbmp.h
@@ -32,7 +32,7 @@ private:
      * Returns a swizzler on success, nullptr on failure
      */
     SkSwizzler* initializeSwizzler(const SkImageInfo& info, const SkPMColor* ctable,
-                                   const Options& opts);
+                                   const Options& opts, int subsetLeft, int subsetHeight);
 
     /*
      * Read a src row from the encoded stream
@@ -51,7 +51,8 @@ private:
     // FIXME: Override onSkipScanlines to avoid swizzling.
     int onGetScanlines(void* dst, int count, size_t dstRowBytes) override;
     Result onStartScanlineDecode(const SkImageInfo& dstInfo, const Options& options,
-            SkPMColor inputColorTable[], int* inputColorCount) override;
+            SkPMColor inputColorTable[], int* inputColorCount, int subsetLeft, int subsetWidth)
+            override;
 
     typedef SkCodec INHERITED;
 };