Remove opaque alpha channel special case

third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.h

Index: third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.h
diff --git a/third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.h b/third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.h
index dec862c04dd80bc31c93bb790634b522496d3a4c..3590e47b2cfbe7fe289ee2fbb2f7dc6a27aef2ae 100644
--- a/third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.h
+++ b/third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.h
@@ -81,17 +81,12 @@ class PLATFORM_EXPORT GIFImageDecoder final : public ImageDecoder {
   // data. If parsing fails, sets the "decode failure" flag.
   void Parse(GIFParseQuery);
 
-  // Reset the alpha tracker for this frame. Before calling this method, the
-  // caller must verify that the frame exists.
-  void OnInitFrameBuffer(size_t) override;
-
   // When the disposal method of the frame is DisposeOverWritePrevious, the
   // next frame will use the previous frame's buffer as its starting state, so
   // we can't take over the data in that case. Before calling this method, the
   // caller must verify that the frame exists.
   bool CanReusePreviousFrameBuffer(size_t) const override;
 
-  bool current_buffer_saw_alpha_;
   mutable int repetition_count_;
   std::unique_ptr<GIFImageReader> reader_;
 };