Change computeOutputColorType() to mimic old behavior

src/codec/SkAndroidCodec.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 "SkAndroidCodec.h"
 #include "SkCodec.h"
 #include "SkCodecPriv.h"
@@ skipping 33 matching lines @@
 
 SkAndroidCodec* SkAndroidCodec::NewFromData(SkData* data, SkPngChunkReader* chunkReader) {
     if (!data) {
         return nullptr;
     }
 
     return NewFromStream(new SkMemoryStream(data), chunkReader);
 }
 
 SkColorType SkAndroidCodec::computeOutputColorType(SkColorType requestedColorType) {
+    // The legacy GIF and WBMP decoders always decode to kIndex_8_SkColorType.
+    // We will maintain this behavior.
+    SkEncodedFormat format = this->getEncodedFormat();
+    if (kGIF_SkEncodedFormat == format || kWBMP_SkEncodedFormat == format) {
+        return kIndex_8_SkColorType;
+    }
+
     SkColorType suggestedColorType = this->getInfo().colorType();
     switch (requestedColorType) {
         case kARGB_4444_SkColorType:
         case kN32_SkColorType:
             return kN32_SkColorType;
         case kIndex_8_SkColorType:
             if (kIndex_8_SkColorType == suggestedColorType) {
                 return kIndex_8_SkColorType;
             }
             break;
         case kAlpha_8_SkColorType:
             // Fall through to kGray_8.  Before kGray_8_SkColorType existed,
             // we allowed clients to request kAlpha_8 when they wanted a
             // grayscale decode.
         case kGray_8_SkColorType:
             if (kGray_8_SkColorType == suggestedColorType) {
                 return kGray_8_SkColorType;
             }
             break;
         case kRGB_565_SkColorType:
             if (kOpaque_SkAlphaType == this->getInfo().alphaType()) {
                 return kRGB_565_SkColorType;
             }
             break;
         default:
             break;
     }
 
+    // Android has limited support for kGray_8 (using kAlpha_8).  We will not
+    // use kGray_8 for Android unless they specifically ask for it.
+    if (kGray_8_SkColorType == suggestedColorType) {
+        return kN32_SkColorType;
+    }
+
+    // This may be kN32_SkColorType or kIndex_8_SkColorType.
     return suggestedColorType;
 }
 
 SkAlphaType SkAndroidCodec::computeOutputAlphaType(bool requestedUnpremul) {
     if (kOpaque_SkAlphaType == this->getInfo().alphaType()) {
         return kOpaque_SkAlphaType;
     }
     return requestedUnpremul ? kUnpremul_SkAlphaType : kPremul_SkAlphaType;
 }
 
@@ skipping 69 matching lines @@
         }
     }
 
     return this->onGetAndroidPixels(info, pixels, rowBytes, *options);
 }
 
 SkCodec::Result SkAndroidCodec::getAndroidPixels(const SkImageInfo& info, void* pixels,
         size_t rowBytes) {
     return this->getAndroidPixels(info, pixels, rowBytes, nullptr);
 }