Fix colorType/alphaType checks in SkCodec

src/codec/SkCodec.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBmpCodec.h"
 #include "SkCodec.h"
 #include "SkCodecPriv.h"
@@ skipping 144 matching lines @@
             return kInvalidParameters;
         }
     } else {
         if (ctableCount) {
             *ctableCount = 0;
         }
         ctableCount = nullptr;
         ctable = nullptr;
     }
 
-    {
-        SkAlphaType canonical;
-        if (!SkColorTypeValidateAlphaType(info.colorType(), info.alphaType(), &canonical)
-            || canonical != info.alphaType())
-        {
-            return kInvalidConversion;
-        }
-    }
-
     if (!this->rewindIfNeeded()) {
         return kCouldNotRewind;
     }
 
     // Default options.
     Options optsStorage;
     if (nullptr == options) {
         options = &optsStorage;
     } else if (options->fSubset) {
         SkIRect subset(*options->fSubset);
@@ skipping 186 matching lines @@
             SkASSERT(1 == linesRequested || this->getInfo().height() == linesRequested);
             const SkImageInfo fillInfo = info.makeWH(info.width(), 1);
             for (int srcY = linesDecoded; srcY < linesRequested; srcY++) {
                 fillDst = SkTAddOffset<void>(dst, this->outputScanline(srcY) * rowBytes);
                 fill_proc(fillInfo, fillDst, rowBytes, fillValue, zeroInit, sampler);
             }
             break;
         }
     }
 }