Remove SkEncodedInfo kUnknown_Color and kUnknown_Alpha from public API

include/codec/SkEncodedInfo.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.
  */
 
 #ifndef SkEncodedInfo_DEFINED
 #define SkEncodedInfo_DEFINED
 
 #include "SkImageInfo.h"
 #include "../private/SkImageInfoPriv.h"
 
 struct SkEncodedInfo {
 public:
 
     enum Alpha {
         kOpaque_Alpha,
         kUnpremul_Alpha,
 
         // Each pixel is either fully opaque or fully transparent.
         // There is no difference between requesting kPremul or kUnpremul.
         kBinary_Alpha,
-
-        // Allows us to have a default constructor.  Should be treated as
-        // invalid.
-        kUnknown_Alpha,
     };
 
     /*
      * We strive to make the number of components per pixel obvious through
      * our naming conventions.
      * Ex: kRGB has 3 components.  kRGBA has 4 components.
      *
      * This sometimes results in redundant Alpha and Color information.
      * Ex: kRGB images must also be kOpaque.
      */
@@ skipping 27 matching lines @@
         // represents 100% ink coverage.  For this reason, we treat CMYK JPEGs
         // as having inverted CMYK.  libjpeg-turbo warns that this may break
         // other applications, but the CMYK JPEGs we see on the web expect to
         // be treated as inverted CMYK.
         kInvertedCMYK_Color,
         kYCCK_Color,
 
         // Used internally to indicate that the decoding library has
         // pre-swizzled to the desired output format.
         kPreSwizzled_Color,
-
-        // Allows us to have a default constructor.  Should be treated as
-        // invalid.
-        kUnknown_Color,
     };
 
     static SkEncodedInfo Make(Color color, Alpha alpha, int bitsPerComponent) {
         SkASSERT(1 == bitsPerComponent ||
                  2 == bitsPerComponent ||
                  4 == bitsPerComponent ||
                  8 == bitsPerComponent ||
                  16 == bitsPerComponent);
 
         switch (color) {
@@ skipping 99 matching lines @@
             case kYUVA_Color:
             case kInvertedCMYK_Color:
             case kYCCK_Color:
                 return 4 * fBitsPerComponent;
             default:
                 SkASSERT(false);
                 return 0;
         }
     }
 
-    SkEncodedInfo()
-        : fColor(kUnknown_Color)
-        , fAlpha(kUnknown_Alpha)
-        , fBitsPerComponent(0)
-    {}
-
 private:
 
     SkEncodedInfo(Color color, Alpha alpha, uint8_t bitsPerComponent)
         : fColor(color)
         , fAlpha(alpha)
         , fBitsPerComponent(bitsPerComponent)
     {}
 
     void setColor(Color color) {
         fColor = color;
     }
 
     Color   fColor;
     Alpha   fAlpha;
     uint8_t fBitsPerComponent;
 
     friend class SkJpegCodec;
 };
 
 #endif