Fix a comment typo: initialize => initial.

Also fix a spelling error: unitialized => uninitialized.

Bug: N/A
Change-Id: Ie61e8be22499660642ae7ab884c32b78b4e9763a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2042323Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#739215}

media/filters/ffmpeg_video_decoder.cc

@@ -139,8 +139,8 @@ int FFmpegVideoDecoder::GetVideoBuffer(struct AVCodecContext* codec_context,
     return AVERROR(EINVAL);
   }
 
-  // FFmpeg expects the initialize allocation to be zero-initialized.  Failure
-  // to do so can lead to unitialized value usage.  See http://crbug.com/390941
+  // FFmpeg expects the initial allocation to be zero-initialized.  Failure to
+  // do so can lead to uninitialized value usage.  See http://crbug.com/390941
   scoped_refptr<VideoFrame> video_frame = frame_pool_.CreateFrame(
       format, coded_size, gfx::Rect(size), natural_size, kNoTimestamp);