Remove opaque alpha channel special case

third_party/WebKit/Source/platform/graphics/DeferredImageDecoderTest.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 328 matching lines @@
             ColorBehavior::TransformToTargetForTesting());
 
     SkImageInfo pix_info = SkImageInfo::MakeN32Premul(1, 1);
 
     size_t row_bytes = pix_info.minRowBytes();
     size_t size = pix_info.getSafeSize(row_bytes);
 
     Vector<char> storage(size);
     SkPixmap pixmap(pix_info, storage.data(), row_bytes);
 
-    // Before decoding, the frame is not known to be opaque.
+    // Before decoding, the frame's alpha is unknown and assumed to be
+    // transparent. This works well with partial decoding, which will be
+    // transparent until the full first frame is decoded.
     sk_sp<SkImage> frame = decoder->CreateFrameAtIndex(0);
     ASSERT_TRUE(frame);
     EXPECT_FALSE(frame->isOpaque());
 
     // Force a lazy decode by reading pixels.
     EXPECT_TRUE(frame->readPixels(pixmap, 0, 0));
 
-    // After decoding, the frame is known to be opaque.
     frame = decoder->CreateFrameAtIndex(0);
     ASSERT_TRUE(frame);
-    EXPECT_TRUE(frame->isOpaque());
+    // When test_gif is true, we use a GIF file which is opaque.
+    // When test_gif is false we use a PNG file instead.
+    // Our PNG handling does not check if an image may be opaque, so it is
+    // treated as transparent.
+    EXPECT_EQ(test_gif, frame->isOpaque());
 
     // Re-generating the opaque-marked frame should not fail.
     EXPECT_TRUE(frame->readPixels(pixmap, 0, 0));
   }
 }
 
 // The DeferredImageDecoder would sometimes assume that a frame was a certain
 // size even if the actual decoder reported it had a size of 0 bytes. This test
 // verifies that it's fixed by always checking with the actual decoder when
 // creating a frame.
@@ skipping 16 matching lines @@
       SharedBuffer::Create(data_->Data(), data_->size());
   EXPECT_EQ(original_data->size(), data_->size());
   lazy_decoder_->SetData(original_data, false);
   RefPtr<SharedBuffer> new_data = lazy_decoder_->Data();
   EXPECT_EQ(original_data->size(), new_data->size());
   EXPECT_EQ(0, std::memcmp(original_data->Data(), new_data->Data(),
                            new_data->size()));
 }
 
 }  // namespace blink