Optimize yuv decoding fail check and remove the usage of unwanted variable.

third_party/WebKit/Source/platform/graphics/ImageFrameGenerator.h

Index: third_party/WebKit/Source/platform/graphics/ImageFrameGenerator.h
diff --git a/third_party/WebKit/Source/platform/graphics/ImageFrameGenerator.h b/third_party/WebKit/Source/platform/graphics/ImageFrameGenerator.h
index 2f32dfcae5afc496215e179d21c9cfaca547ab05..30f7b71e90613c55ed98b4297367f3dc62359bdc 100644
--- a/third_party/WebKit/Source/platform/graphics/ImageFrameGenerator.h
+++ b/third_party/WebKit/Source/platform/graphics/ImageFrameGenerator.h
@@ -145,7 +145,6 @@ class PLATFORM_EXPORT ImageFrameGenerator final
 
   const bool is_multi_frame_;
   bool decode_failed_;
-  bool yuv_decoding_failed_;

[scroggo_chromium, 2017/06/15 14:45:22]

I don't understand the removal of this variable. The purpose is so that we do
not try to YUV decode a second time if we failed previously.

Does something else prevent us from retrying? Or is it okay to retry for some
reason?

   size_t frame_count_;
   Vector<bool> has_alpha_;