replace kIgnore_SkAlphaType with kUnknown_SkAlphaType

src/core/SkConfig8888.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkCanvas.h"
 #include "SkConfig8888.h"
@@ skipping 36 matching lines @@
     for (int i = 0; i < count; ++i) {
         dst[i] = convert32<doSwapRB, doAlpha>(src[i]);
     }
 }
 
 static bool is_32bit_colortype(SkColorType ct) {
     return kRGBA_8888_SkColorType == ct || kBGRA_8888_SkColorType == ct;
 }
 
 static AlphaVerb compute_AlphaVerb(SkAlphaType src, SkAlphaType dst) {
-    SkASSERT(kIgnore_SkAlphaType != src);
-    SkASSERT(kIgnore_SkAlphaType != dst);
+    SkASSERT(kUnknown_SkAlphaType != src);
+    SkASSERT(kUnknown_SkAlphaType != dst);
 
     if (kOpaque_SkAlphaType == src || kOpaque_SkAlphaType == dst || src == dst) {
         return kNothing_AlphaVerb;
     }
     if (kPremul_SkAlphaType == dst) {
         SkASSERT(kUnpremul_SkAlphaType == src);
         return kPremul_AlphaVerb;
     } else {
         SkASSERT(kPremul_SkAlphaType == src);
         SkASSERT(kUnpremul_SkAlphaType == dst);
@@ skipping 177 matching lines @@
 
         SkPaint  paint;
         paint.setDither(true);
 
         canvas->clear(0);
         canvas->drawBitmap(bm, 0, 0, &paint);
         return true;
     }
 }