Do not create BmpMaskCodecs with invalid bits per pixel

src/codec/SkBmpCodec.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 "SkBmpMaskCodec.h"
 #include "SkBmpRLECodec.h"
@@ skipping 414 matching lines @@
         case 1:
         case 2:
         case 4:
         case 8:
             // However, we cannot in RLE format since we may need to leave some
             // pixels as transparent.  Similarly, we also cannot for ICO images
             // since we may need to apply a transparent mask.
             if (kRLE_BmpInputFormat != inputFormat && !inIco) {
                 colorType = kIndex_8_SkColorType;
             }
+
+            // Mask bmps must have 16, 24, or 32 bits per pixel.
+            if (kBitMask_BmpInputFormat == inputFormat) {
+                SkCodecPrintf("Error: invalid input value of bits per pixel for mask bmp.\n");
+                return false;
+            }
         case 24:
         case 32:
             break;
         default:
             SkCodecPrintf("Error: invalid input value for bits per pixel.\n");
             return false;
     }
 
     // Check that input bit masks are valid and create the masks object
     SkAutoTDelete<SkMasks>
@@ skipping 135 matching lines @@
 }
 
 bool SkBmpCodec::skipRows(int count) {
     const size_t bytesToSkip = count * fSrcRowBytes;
     return this->stream()->skip(bytesToSkip) == bytesToSkip;
 }
 
 bool SkBmpCodec::onSkipScanlines(int count) {
     return this->skipRows(count);
 }