Remove opaque alpha channel special case

third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h

Index: third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h
diff --git a/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h b/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h
index a41bf4e6d6b75d7d5ee0f9d2eae1ea468fcc6ec6..5e954dd2080be326daa75b5a1d50a5d5e8dcf4ec 100644
--- a/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h
+++ b/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h
@@ -347,18 +347,6 @@ class PLATFORM_EXPORT ImageDecoder {
   //         false otherwise.
   bool PostDecodeProcessing(size_t);
 
-  // The GIF and PNG decoders set the default alpha setting of the ImageFrame to
-  // true. When the frame rect does not contain any (semi-) transparent pixels,
-  // this may need to be changed to false. This depends on whether the required
-  // previous frame adds transparency to the image, outside of the frame rect.
-  // This methods corrects the alpha setting of the frame buffer to false when
-  // the whole frame is opaque.
-  //
-  // This method should be called by the GIF and PNG decoder when the pixels in
-  // the frame rect do *not* contain any transparent pixels. Before calling
-  // this method, the caller must verify that the frame exists.
-  void CorrectAlphaWhenFrameBufferSawNoAlpha(size_t);
-
   RefPtr<SegmentReader> data_;  // The encoded data.
   Vector<ImageFrame, 1> frame_buffer_cache_;
   const bool premultiply_alpha_;