Monitor VideoResourceUpdater reusing destructed resource in Debug mode.

cc/resources/video_resource_updater.cc

Index: cc/resources/video_resource_updater.cc
diff --git a/cc/resources/video_resource_updater.cc b/cc/resources/video_resource_updater.cc
index e6827ee3315c57c4dc789be81d3220948e547c74..2a1a0c0261a9af863f5f3653b3ab262b8e278ad5 100644
--- a/cc/resources/video_resource_updater.cc
+++ b/cc/resources/video_resource_updater.cc
@@ -29,6 +29,10 @@ namespace {
 
 const ResourceFormat kRGBResourceFormat = RGBA_8888;
 
+// This key is used to mark the userdata in VideoFrame to indicate that its
+// content has been cached in VideoResourceUpdater.
+const char kResourceUploadedKey[] = "ResourceUploadedFlag";
+
 VideoFrameExternalResources::ResourceType ResourceTypeForVideoFrame(
     media::VideoFrame* video_frame) {
   switch (video_frame->format()) {
@@ -134,16 +138,19 @@ bool VideoResourceUpdater::PlaneResourceMatchesUniqueID(
     size_t plane_index) {
   return plane_resource.frame_ptr == video_frame &&
          plane_resource.plane_index == plane_index &&
-         plane_resource.timestamp == video_frame->timestamp();
+         plane_resource.timestamp == video_frame->timestamp() &&

[danakj, 2016/02/23 23:55:09]

Can you instead just return false if the timestamps are 0?

[xjz, 2016/02/24 00:01:28]

The actual timestamp could be 0. It is difficult to check whether the timestamp
is correctly set (unique for each frame) here.

[danakj, 2016/02/24 00:07:08]

Oh :/ I don't really like cc setting things on a VideoFrame for this here, it
feels very much like a layering violation.

Can the video decoders set some incrementing id on VideoFrames that they
generate or something, and it could use that, since there is this new need to
tell when a VideoFrame is repeated? That feels like something the VideoFrame
should provide then, rather than hacking in this general thing where cc sets a
flag only it knows about.

[xjz, 2016/02/24 21:57:58]

This sounds equivalent to asking decoders correctly set the timestamps.  

+         video_frame->GetUserData(kResourceUploadedKey);
 }
 
 void VideoResourceUpdater::SetPlaneResourceUniqueId(
-    const media::VideoFrame* video_frame,
+    media::VideoFrame* video_frame,
     size_t plane_index,
     PlaneResource* plane_resource) {
   plane_resource->frame_ptr = video_frame;
   plane_resource->plane_index = plane_index;
   plane_resource->timestamp = video_frame->timestamp();
+  video_frame->SetUserData(kResourceUploadedKey,
+                           new base::SupportsUserData::Data());
 }
 
 VideoFrameExternalResources::VideoFrameExternalResources()