Fix memory leak in VideoToolbox encoder.

webrtc/sdk/objc/Framework/Classes/VideoToolbox/nalu_rewriter.cc

Index: webrtc/sdk/objc/Framework/Classes/VideoToolbox/nalu_rewriter.cc
diff --git a/webrtc/sdk/objc/Framework/Classes/VideoToolbox/nalu_rewriter.cc b/webrtc/sdk/objc/Framework/Classes/VideoToolbox/nalu_rewriter.cc
index 47afe9561e7edffcaf1b92d2dcae16f794924633..e6cd7eb0cd7cff0b75c8ea2b2ff6d276277e72e9 100644
--- a/webrtc/sdk/objc/Framework/Classes/VideoToolbox/nalu_rewriter.cc
+++ b/webrtc/sdk/objc/Framework/Classes/VideoToolbox/nalu_rewriter.cc
@@ -33,10 +33,10 @@ bool H264CMSampleBufferToAnnexBBuffer(
     CMSampleBufferRef avcc_sample_buffer,
     bool is_keyframe,
     rtc::Buffer* annexb_buffer,
-    webrtc::RTPFragmentationHeader** out_header) {
+    std::unique_ptr<RTPFragmentationHeader> *out_header) {
   RTC_DCHECK(avcc_sample_buffer);
   RTC_DCHECK(out_header);
-  *out_header = nullptr;
+  out_header->reset(nullptr);
 
   // Get format description from the sample buffer.
   CMVideoFormatDescriptionRef description =
@@ -143,8 +143,7 @@ bool H264CMSampleBufferToAnnexBBuffer(
   }
   RTC_DCHECK_EQ(bytes_remaining, (size_t)0);
 
-  std::unique_ptr<webrtc::RTPFragmentationHeader> header;
-  header.reset(new webrtc::RTPFragmentationHeader());
+  auto header = new webrtc::RTPFragmentationHeader();

[magjed_webrtc, 2017/08/29 11:35:02]

Can't we put it in |out_header| immediately, i.e. out_header->reset(new
webrtc::RTPFragmentationHeader())?

[kthelgason, 2017/08/29 11:39:45]

Sure, I just did this to keep the diff small and to avoid having to write
(*out_header)->thing = other_thing; 
This looks nicer :)

[magjed_webrtc, 2017/08/30 09:06:10]

I want a variable always owning the memory in an std::unique_ptr. I agree typing
is ugly (*out_header), so you can also do:
std::unique_ptr<webrtc::RTPFragmentationHeader> header(
    new webrtc::RTPFragmentationHeader());
  ...
  header->...
  ...
*out_header = std::move(header);

But I don't want the memory to be held in a raw pointer, even if it's just
locally. It will be more robust against future changes if we always keep it in a
std::unique_ptr.

[kthelgason, 2017/08/30 09:13:41]

You're right, I've fixed this now. Thanks!

   header->VerifyAndAllocateFragmentationHeader(frag_offsets.size());
   RTC_DCHECK_EQ(frag_lengths.size(), frag_offsets.size());
   for (size_t i = 0; i < frag_offsets.size(); ++i) {
@@ -153,7 +152,7 @@ bool H264CMSampleBufferToAnnexBBuffer(
     header->fragmentationPlType[i] = 0;
     header->fragmentationTimeDiff[i] = 0;
   }
-  *out_header = header.release();
+  out_header->reset(header);

[henrika_webrtc, 2017/08/29 10:37:12]

Should it be documented that we deleted and release here?

   CFRelease(contiguous_buffer);
   return true;
 }