Fix ChunkDemuxer seek deadlock

media/filters/video_renderer_base.cc

Index: media/filters/video_renderer_base.cc
diff --git a/media/filters/video_renderer_base.cc b/media/filters/video_renderer_base.cc
index df7350c23d6b640df37cb2101c18a0fe12b30b52..38f67bfbfeab0706620995a143e6bd4cc64435e2 100644
--- a/media/filters/video_renderer_base.cc
+++ b/media/filters/video_renderer_base.cc
@@ -336,8 +336,6 @@ void VideoRendererBase::PutCurrentFrame(scoped_refptr<VideoFrame> frame) {
 }
 
 void VideoRendererBase::FrameReady(scoped_refptr<VideoFrame> frame) {
-  DCHECK(frame);
-
   base::AutoLock auto_lock(lock_);
   DCHECK_NE(state_, kUninitialized);
   DCHECK_NE(state_, kStopped);
@@ -352,41 +350,45 @@ void VideoRendererBase::FrameReady(scoped_refptr<VideoFrame> frame) {
     return;
   }
 
-  // Discard frames until we reach our desired seek timestamp.
-  if (state_ == kSeeking && !frame->IsEndOfStream() &&
-      (frame->GetTimestamp() + frame->GetDuration()) <= seek_timestamp_) {
-    AttemptRead_Locked();
-    return;
-  }
-
-  // Adjust the incoming frame if its rendering stop time is past the duration
-  // of the video itself. This is typically the last frame of the video and
-  // occurs if the container specifies a duration that isn't a multiple of the
-  // frame rate.  Another way for this to happen is for the container to state a
-  // smaller duration than the largest packet timestamp.
-  if (!frame->IsEndOfStream()) {
-    if (frame->GetTimestamp() > host()->GetDuration())
-      frame->SetTimestamp(host()->GetDuration());
-    if ((frame->GetTimestamp() + frame->GetDuration()) > host()->GetDuration())
-      frame->SetDuration(host()->GetDuration() - frame->GetTimestamp());
-  }
-
-  // This one's a keeper! Place it in the ready queue.
-  ready_frames_.push_back(frame);
-  DCHECK_LE(NumFrames_Locked(), limits::kMaxVideoFrames);
-  frame_available_.Signal();
+  if (frame) {

[Ami GONE FROM CHROMIUM, 2012/01/27 23:44:58]

reverse test & early-return?

[acolwell GONE FROM CHROMIUM, 2012/01/29 03:00:41]

Done.

+    // Discard frames until we reach our desired seek timestamp.
+    if (state_ == kSeeking && !frame->IsEndOfStream() &&
+        (frame->GetTimestamp() + frame->GetDuration()) <= seek_timestamp_) {
+      AttemptRead_Locked();
+      return;
+    }
 
-  PipelineStatistics statistics;
-  statistics.video_frames_decoded = 1;
-  statistics_callback_.Run(statistics);
+    // Adjust the incoming frame if its rendering stop time is past the duration
+    // of the video itself. This is typically the last frame of the video and
+    // occurs if the container specifies a duration that isn't a multiple of the
+    // frame rate.  Another way for this to happen is for the container to state
+    // a smaller duration than the largest packet timestamp.
+    if (!frame->IsEndOfStream()) {
+      base::TimeDelta duration = host()->GetDuration();

[Ami GONE FROM CHROMIUM, 2012/01/27 23:44:58]

IMO this is a worsening of readability, since there are two "durations" involved
here (frame & host).  Revert?

[acolwell GONE FROM CHROMIUM, 2012/01/29 03:00:41]

Done.

+      if (frame->GetTimestamp() > duration)
+        frame->SetTimestamp(duration);
+      if ((frame->GetTimestamp() + frame->GetDuration()) > duration)
+        frame->SetDuration(duration - frame->GetTimestamp());
+    }
 
-  // Always request more decoded video if we have capacity. This serves two
-  // purposes:
-  //   1) Prerolling while paused
-  //   2) Keeps decoding going if video rendering thread starts falling behind
-  if (NumFrames_Locked() < limits::kMaxVideoFrames && !frame->IsEndOfStream()) {
-    AttemptRead_Locked();
-    return;
+    // This one's a keeper! Place it in the ready queue.
+    ready_frames_.push_back(frame);
+    DCHECK_LE(NumFrames_Locked(), limits::kMaxVideoFrames);
+    frame_available_.Signal();
+
+    PipelineStatistics statistics;
+    statistics.video_frames_decoded = 1;
+    statistics_callback_.Run(statistics);
+
+    // Always request more decoded video if we have capacity. This serves two
+    // purposes:
+    //   1) Prerolling while paused
+    //   2) Keeps decoding going if video rendering thread starts falling behind
+    if (NumFrames_Locked() < limits::kMaxVideoFrames &&
+        !frame->IsEndOfStream()) {
+      AttemptRead_Locked();
+      return;
+    }
   }
 
   // If we're at capacity or end of stream while seeking we need to transition