Support decoding opaque to *premul

src/codec/SkBmpStandardCodec.h

 /*
  * 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 "SkColorTable.h"
 #include "SkImageInfo.h"
@@ skipping 37 matching lines @@
 
     bool onInIco() const override {
         return fInIco;
     }
 
     SkCodec::Result prepareToDecode(const SkImageInfo& dstInfo,
             const SkCodec::Options& options, SkPMColor inputColorPtr[],
             int* inputColorCount) override;
 
 
-    uint32_t onGetFillValue(SkColorType colorType, SkAlphaType alphaType) const override;
+    uint32_t onGetFillValue(SkColorType) const override;
 
     SkSampler* getSampler(bool createIfNecessary) override {
         SkASSERT(fSwizzler);
         return fSwizzler;
     }
 
 private:
 
     /*
      * Creates the color table
@@ skipping 19 matching lines @@
     const uint32_t                      fBytesPerColor;
     const uint32_t                      fOffset;
     SkAutoTDelete<SkSwizzler>           fSwizzler;
     const size_t                        fSrcRowBytes;
     SkAutoTDeleteArray<uint8_t>         fSrcBuffer;
     const bool                          fInIco;
     const size_t                        fAndMaskRowBytes; // only used for fInIco decodes
 
     typedef SkBmpCodec INHERITED;
 };