Index8 GPU and CPU raster support.

src/core/SkImageGenerator.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkImageGenerator.h"
 #include "SkNextID.h"
 
@@ skipping 159 matching lines @@
     }
 
     bitmap->lockPixels();
     if (!bitmap->getPixels()) {
         return reset_and_return_false(bitmap);
     }
 
     int ctCount = 0;
     if (!this->getPixels(bitmap->info(), bitmap->getPixels(), bitmap->rowBytes(),
                          ctStorage, &ctCount)) {
+        // Generator failing to decode to declared colorType, could decode to N32.
+        // This is important for Chromium Index8 decoding - GIF multiframe animation frames are
+        // decoded to Index8 format by default but in rare cases some of the frames are N32.
+        if (bitmap->colorType() != kN32_SkColorType) {
+            bitmap->reset();
+            info = SkImageInfo::MakeN32(info.width(), info.height(), info.alphaType());
+            return tryGenerateBitmap(bitmap, &info, allocator);
+        }
         return reset_and_return_false(bitmap);
     }
 
     if (ctCount > 0) {
         SkASSERT(kIndex_8_SkColorType == bitmap->colorType());
         // we and bitmap should be owners
         SkASSERT(!ctable->unique());
 
         // Now we need to overwrite the ctable we built earlier, with the correct colors.
         // This does mean that we may have made the table too big, but that cannot be avoided
@@ skipping 24 matching lines @@
     if (nullptr == data) {
         return nullptr;
     }
     if (gFactory) {
         if (SkImageGenerator* generator = gFactory(data)) {
             return generator;
         }
     }
     return SkImageGenerator::NewFromEncodedImpl(data);
 }