Revert of Fix colorType/alphaType checks in SkCodec

src/codec/SkBmpMaskCodec.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 "SkBmpMaskCodec.h"
 #include "SkCodecPriv.h"
 #include "SkColorPriv.h"
@@ skipping 40 matching lines @@
     }
 
     int rows = this->decodeRows(dstInfo, dst, dstRowBytes, opts);
     if (rows != dstInfo.height()) {
         *rowsDecoded = rows;
         return kIncompleteInput;
     }
     return kSuccess;
 }
 
+bool SkBmpMaskCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options& options) {
+    // Create the swizzler
+    fMaskSwizzler.reset(SkMaskSwizzler::CreateMaskSwizzler(dstInfo, this->getInfo(), fMasks,
+            this->bitsPerPixel(), options));
+
+    if (nullptr == fMaskSwizzler.get()) {
+        return false;
+    }
+
+    return true;
+}
+
 SkCodec::Result SkBmpMaskCodec::prepareToDecode(const SkImageInfo& dstInfo,
         const SkCodec::Options& options, SkPMColor inputColorPtr[], int* inputColorCount) {
-    // Initialize the mask swizzler
-    fMaskSwizzler.reset(SkMaskSwizzler::CreateMaskSwizzler(dstInfo, this->getInfo(), fMasks,
-            this->bitsPerPixel(), options));
-    SkASSERT(fMaskSwizzler);
+    // Initialize a the mask swizzler
+    if (!this->initializeSwizzler(dstInfo, options)) {
+        SkCodecPrintf("Error: cannot initialize swizzler.\n");
+        return SkCodec::kInvalidConversion;
+    }
 
     return SkCodec::kSuccess;
 }
 
 /*
  * Performs the decoding
  */
 int SkBmpMaskCodec::decodeRows(const SkImageInfo& dstInfo,
                                            void* dst, size_t dstRowBytes,
                                            const Options& opts) {
     // Iterate over rows of the image
     uint8_t* srcRow = fSrcBuffer.get();
     const int height = dstInfo.height();
     for (int y = 0; y < height; y++) {
         // Read a row of the input
         if (this->stream()->read(srcRow, fSrcRowBytes) != fSrcRowBytes) {
             SkCodecPrintf("Warning: incomplete input stream.\n");
             return y;
         }
 
         // Decode the row in destination format
         uint32_t row = this->getDstRow(y, height);
         void* dstRow = SkTAddOffset<void>(dst, row * dstRowBytes);
         fMaskSwizzler->swizzle(dstRow, srcRow);
     }
 
     // Finished decoding the entire image
     return height;
 }