Remove opaque alpha channel special case

third_party/WebKit/Source/platform/image-decoders/jpeg/JPEGImageDecoder.cpp

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  *
  * Portions are Copyright (C) 2001-6 mozilla.org
  *
  * Other contributors:
  *   Stuart Parmenter <stuart@mozilla.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ skipping 925 matching lines @@
               static_cast<JDIMENSION>(decoded_size_.Height()));
 
     if (!buffer.AllocatePixelData(info->output_width, info->output_height,
                                   ColorSpaceForSkImages()))
       return SetFailed();
 
     buffer.ZeroFillPixelData();
     // The buffer is transparent outside the decoded area while the image is
     // loading. The image will be marked fully opaque in Complete().
     buffer.SetStatus(ImageFrame::kFramePartial);
-    buffer.SetHasAlpha(true);

[scroggo_chromium, 2017/05/31 14:27:50]

This removal is related, but isn't called out in the change description. It
won't change anything (has_alpha_ is initialized to false, and the ImageFrame is
considered to have alpha until it's FrameComplete, regardless of has_alpha). Do
we already have a test that verifies this?

[cblume, 2017/08/10 20:52:12]

I just ran it before & after on the bots. It looks like this is not tested.

Aside from that, you are right that it is unrelated. It makes more sense to
leave it and correctly mark a partial image as having transparency.

I've added it back in. Since that was the only change to this file, the file was
removed from the list of changes.

 
     // For JPEGs, the frame always fills the entire image.
     buffer.SetOriginalFrameRect(IntRect(IntPoint(), Size()));
   }
 
 #if defined(TURBO_JPEG_RGB_SWIZZLE)
   if (turboSwizzled(info->out_color_space)) {
     while (info->output_scanline < info->output_height) {
       unsigned char* row = reinterpret_cast_ptr<unsigned char*>(
           buffer.GetAddr(0, info->output_scanline));
@@ skipping 51 matching lines @@
   // has failed.
   if (!reader_->Decode(only_size) && IsAllDataReceived())
     SetFailed();
 
   // If decoding is done or failed, we don't need the JPEGImageReader anymore.
   if (IsComplete(this, only_size) || Failed())
     reader_.reset();
 }
 
 }  // namespace blink