Revert of [Cast] Software encoder support for varying video frame sizes.

media/cast/test/utility/video_utility.h

Index: media/cast/test/utility/video_utility.h
diff --git a/media/cast/test/utility/video_utility.h b/media/cast/test/utility/video_utility.h
index a446a8020e40170713aac5c7e984bed8e3623a37..32bd5c042c3551030446f9278841f8084e85a5b8 100644
--- a/media/cast/test/utility/video_utility.h
+++ b/media/cast/test/utility/video_utility.h
@@ -17,8 +17,7 @@
 double I420SSIM(const scoped_refptr<media::VideoFrame>& frame1,
                 const scoped_refptr<media::VideoFrame>& frame2);
 
-// Populate a video |frame| with a plaid pattern, cycling from the given
-// |start_value|.
+// Populate a video frame with values starting with the given start value.
 // Width, height and stride should be set in advance.
 // Memory is allocated within the function.
 void PopulateVideoFrame(VideoFrame* frame, int start_value);