Use ParamTraits for media::BitstreamBuffer.

media/base/bitstream_buffer.cc

Index: media/base/bitstream_buffer.cc
diff --git a/media/base/bitstream_buffer.cc b/media/base/bitstream_buffer.cc
index 49caf5b8215cf03622a04e9a673bce76081d8355..9966aaca6baf028d335af7b6a0b11f59c1c59f2b 100644
--- a/media/base/bitstream_buffer.cc
+++ b/media/base/bitstream_buffer.cc
@@ -6,6 +6,9 @@
 
 namespace media {
 
+BitstreamBuffer::BitstreamBuffer()
+    : id_(-1), size_(0), presentation_timestamp_(kNoTimestamp()) {}
+
 BitstreamBuffer::BitstreamBuffer(int32_t id,
                                  base::SharedMemoryHandle handle,
                                  size_t size)