Add packetization and coding/decoding of feedback message format.

webrtc/modules/rtp_rtcp/source/byte_io.h

Index: webrtc/modules/rtp_rtcp/source/byte_io.h
diff --git a/webrtc/modules/rtp_rtcp/source/byte_io.h b/webrtc/modules/rtp_rtcp/source/byte_io.h
index 2617806dd941205c813a0b0c535f949429a6c97e..c0d519ba4a658749fb5510aca63113c137b92bb7 100644
--- a/webrtc/modules/rtp_rtcp/source/byte_io.h
+++ b/webrtc/modules/rtp_rtcp/source/byte_io.h
@@ -50,6 +50,7 @@ template<typename T, unsigned int B = sizeof(T),
 class ByteReader {
  public:
   static T ReadBigEndian(const uint8_t* data) {
+    static_assert(B <= sizeof(T), "Target size too large");
     if (is_signed && B < sizeof(T)) {
       return SignExtend(InternalReadBigEndian(data));
     }
@@ -57,6 +58,7 @@ class ByteReader {
   }
 
   static T ReadLittleEndian(const uint8_t* data) {
+    static_assert(B <= sizeof(T), "Target size too large");
     if (is_signed && B < sizeof(T)) {
       return SignExtend(InternalReadLittleEndian(data));
     }
@@ -106,12 +108,14 @@ template<typename T, unsigned int B = sizeof(T)>
 class ByteWriter {
  public:
   static void WriteBigEndian(uint8_t* data, T val) {
+    static_assert(B <= sizeof(T), "Target size too large");
     for (unsigned int i = 0; i < B; ++i) {
       data[i] = val >> ((B - 1 - i) * 8);
     }
   }
 
   static void WriteLittleEndian(uint8_t* data, T val) {
+    static_assert(B <= sizeof(T), "Target size too large");
     for (unsigned int i = 0; i < B; ++i) {
       data[i] = val >> (i * 8);
     }