Make SkAndroidCodec support ico

include/codec/SkCodec.h

Index: include/codec/SkCodec.h
diff --git a/include/codec/SkCodec.h b/include/codec/SkCodec.h
index 41995acb05e66529f108c6cc3f4450a2f0d19310..86ed67f14ddef5399a6615c4f4f06f74383a445e 100644
--- a/include/codec/SkCodec.h
+++ b/include/codec/SkCodec.h
@@ -382,6 +382,8 @@ public:
     /**
      *  An enum representing the order in which scanlines will be returned by
      *  the scanline decoder.
+     *
+     *  This is undefined before startScanlineDecode() is called.
      */
     SkScanlineOrder getScanlineOrder() const { return this->onGetScanlineOrder(); }
 
@@ -594,5 +596,6 @@ private:
     virtual SkSampler* getSampler(bool /*createIfNecessary*/) { return nullptr; }
 
     friend class SkSampledCodec;
+    friend class SkIcoCodec;
 };
 #endif // SkCodec_DEFINED