Change H264AnnexBBitstreamConverter to use AVCDecoderConfigurationRecord.

media/formats/mp4/box_reader.h

Index: media/formats/mp4/box_reader.h
diff --git a/media/formats/mp4/box_reader.h b/media/formats/mp4/box_reader.h
index d4b608e78f9ea80c76f0dc6c95d20005d9b5c7ce..1ba0294bff3728799749fd862015053ee4b0e0ca 100644
--- a/media/formats/mp4/box_reader.h
+++ b/media/formats/mp4/box_reader.h
@@ -29,7 +29,10 @@ struct MEDIA_EXPORT Box {
 class MEDIA_EXPORT BufferReader {
  public:
   BufferReader(const uint8* buf, const int size)
-    : buf_(buf), size_(size), pos_(0) {}
+      : buf_(buf), size_(size), pos_(0) {
+    CHECK(buf);
+    CHECK_GE(size, 0);
+  }
 
   bool HasBytes(int count) { return (pos() + count <= size()); }