Revert of Checking for valid colorType, alphaType, colorSpace in SkCodec

src/codec/SkGifCodec.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 "SkCodecPriv.h"
 #include "SkColorPriv.h"
 #include "SkColorTable.h"
@@ skipping 432 matching lines @@
         sk_memset32(colorPtr, 0xFF000000, maxColors);
     }
 
     fColorTable.reset(new SkColorTable(colorPtr, maxColors));
     copy_color_table(dstInfo, this->fColorTable, inputColorPtr, inputColorCount);
 }
 
 SkCodec::Result SkGifCodec::prepareToDecode(const SkImageInfo& dstInfo, SkPMColor* inputColorPtr,
         int* inputColorCount, const Options& opts) {
     // Check for valid input parameters
-    if (!conversion_possible_ignore_color_space(dstInfo, this->getInfo())) {
-        return gif_error("Cannot convert input type to output type.\n", kInvalidConversion);
+    if (!conversion_possible(dstInfo, this->getInfo())) {
+        return gif_error("Cannot convert input type to output type.\n",
+                kInvalidConversion);
     }
 
     // Initialize color table and copy to the client if necessary
     this->initializeColorTable(dstInfo, inputColorPtr, inputColorCount);
 
     this->initializeSwizzler(dstInfo, opts);
     return kSuccess;
 }
 
 void SkGifCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options& opts) {
@@ skipping 132 matching lines @@
 int SkGifCodec::onOutputScanline(int inputScanline) const {
     if (fGif->Image.Interlace) {
         if (inputScanline < fFrameRect.top() || inputScanline >= fFrameRect.bottom()) {
             return inputScanline;
         }
         return get_output_row_interlaced(inputScanline - fFrameRect.top(), fFrameRect.height()) +
                 fFrameRect.top();
     }
     return inputScanline;
 }