Support more swizzles to 565 in SkCodec

src/codec/SkCodec_libgif.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 "SkCodec_libgif.h"
 #include "SkCodecPriv.h"
 #include "SkColorPriv.h"
@@ skipping 193 matching lines @@
     return NULL;
 }
 
 SkGifCodec::SkGifCodec(const SkImageInfo& srcInfo, SkStream* stream,
                        GifFileType* gif)
     : INHERITED(srcInfo, stream)
     , fGif(gif)
 {}
 
 /*
- * Checks if the conversion between the input image and the requested output
- * image has been implemented
- */
-static bool conversion_possible(const SkImageInfo& dst,
-                                const SkImageInfo& src) {
-    // Ensure that the profile type is unchanged
-    if (dst.profileType() != src.profileType()) {
-        return false;
-    }
-
-    // Check for supported color and alpha types
-    switch (dst.colorType()) {
-        case kN32_SkColorType:
-            return kPremul_SkAlphaType == dst.alphaType() ||
-                    kUnpremul_SkAlphaType == dst.alphaType();
-        case kIndex_8_SkColorType:
-            return kPremul_SkAlphaType == dst.alphaType() ||
-                    kUnpremul_SkAlphaType == dst.alphaType();
-        default:
-            return false;
-    }
-}
-
-/*
  * Initiates the gif decode
  */
 SkCodec::Result SkGifCodec::onGetPixels(const SkImageInfo& dstInfo,
                                         void* dst, size_t dstRowBytes,
                                         const Options& opts,
                                         SkPMColor* inputColorPtr,
                                         int* inputColorCount) {
     // Rewind if necessary
     SkCodec::RewindState rewindState = this->rewindIfNeeded();
     if (rewindState == kCouldNotRewind_RewindState) {
@@ skipping 323 matching lines @@
                 // giflib returns an error code if the record type is not known.
                 // We should catch this error immediately.
                 SkASSERT(false);
                 break;
         }
     } while (TERMINATE_RECORD_TYPE != recordType);
 
     return gif_error("Could not find any images to decode in gif file.\n",
             kInvalidInput);
 }