Remove memset from VideoFrame and mark buffer as unpoisoned

- I removed the memset from AllocateYUV as it looks unnecessary except for FFmpegVideoDecoder.
- FFmpegVideoDecoder marks the incoming buffer from VideoFramePool as unpoisoned.

BUG=508220

Review URL: https://codereview.chromium.org/1227383003

Cr-Commit-Position: refs/heads/master@{#339304}

3 files changed, 4 insertions, 16 deletions

diff --git a/media/base/video_frame.cc b/media/base/video_frame.cc
index 2c3fefe..51269a8 100644
--- a/media/base/video_frame.cc
+++ b/media/base/video_frame.cc
@@ -856,11 +856,8 @@ void VideoFrame::AllocateYUV() {
   DCHECK(IsValidPlane(kUPlane, format_));
   data_size += strides_[kUPlane] + kFrameSizePadding;
 
-  // FFmpeg expects the initialize allocation to be zero-initialized.  Failure
-  // to do so can lead to unitialized value usage.  See http://crbug.com/390941
   uint8* data = reinterpret_cast<uint8*>(
       base::AlignedAlloc(data_size, kFrameAddressAlignment));
-  memset(data, 0, data_size);
 
   for (size_t plane = 0; plane < NumPlanes(format_); ++plane)
     data_[plane] = data + offset[plane];
diff --git a/media/base/video_frame_unittest.cc b/media/base/video_frame_unittest.cc
index 5a316ac..1096766 100644
--- a/media/base/video_frame_unittest.cc
+++ b/media/base/video_frame_unittest.cc
@@ -330,19 +330,6 @@ TEST(VideoFrame,
   EXPECT_EQ(release_sync_point, called_sync_point);
 }
 
-TEST(VideoFrame, ZeroInitialized) {
-  const int kWidth = 64;
-  const int kHeight = 48;
-  const base::TimeDelta kTimestamp = base::TimeDelta::FromMicroseconds(1337);
-
-  gfx::Size size(kWidth, kHeight);
-  scoped_refptr<media::VideoFrame> frame = VideoFrame::CreateFrame(
-      media::PIXEL_FORMAT_YV12, size, gfx::Rect(size), size, kTimestamp);
-
-  for (size_t i = 0; i < VideoFrame::NumPlanes(frame->format()); ++i)
-    EXPECT_EQ(0, frame->data(i)[0]);
-}
-
 TEST(VideoFrameMetadata, SetAndThenGetAllKeysForAllTypes) {
   VideoFrameMetadata metadata;
 
diff --git a/media/filters/ffmpeg_video_decoder.cc b/media/filters/ffmpeg_video_decoder.cc
index c3f1c68..3a72677 100644
--- a/media/filters/ffmpeg_video_decoder.cc
+++ b/media/filters/ffmpeg_video_decoder.cc
@@ -127,6 +127,10 @@ int FFmpegVideoDecoder::GetVideoBuffer(struct AVCodecContext* codec_context,
 
   scoped_refptr<VideoFrame> video_frame = frame_pool_.CreateFrame(
       format, coded_size, gfx::Rect(size), natural_size, kNoTimestamp());
+#if defined(MEMORY_SANITIZER)
+  MSAN_UNPOISON(video_frame->data(0),
+                VideoFrame::AllocationSize(format, coded_size));
+#endif
 
   // Prefer the color space from the codec context. If it's not specified (or is
   // set to an unsupported value), fall back on the value from the config.