Use |nullptr| instead of |NULL| in the h264_bitstream_buffer.cc.

Bug: 1080832
Change-Id: I4ff90e0040dfba8a2432d51f4f3dcdd7aa2e7f65
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2495505
Commit-Queue: Łukasz Anforowicz <lukasza@chromium.org>
Commit-Queue: Thomas Guilbert <tguilbert@chromium.org>
Auto-Submit: Łukasz Anforowicz <lukasza@chromium.org>
Reviewed-by: Thomas Guilbert <tguilbert@chromium.org>
Cr-Commit-Position: refs/heads/master@{#820322}

media/filters/h264_bitstream_buffer.cc

@@ -8,18 +8,18 @@
 
 namespace media {
 
-H264BitstreamBuffer::H264BitstreamBuffer() : data_(NULL) {
+H264BitstreamBuffer::H264BitstreamBuffer() : data_(nullptr) {
   Reset();
 }
 
 H264BitstreamBuffer::~H264BitstreamBuffer() {
   free(data_);
-  data_ = NULL;
+  data_ = nullptr;
 }
 
 void H264BitstreamBuffer::Reset() {
   free(data_);
-  data_ = NULL;
+  data_ = nullptr;
 
   capacity_ = 0;
   pos_ = 0;