Add WriteUVarint to ByteBufferWriter and ReadUVarint to ByteBufferReader

webrtc/base/bytebuffer.h

Index: webrtc/base/bytebuffer.h
diff --git a/webrtc/base/bytebuffer.h b/webrtc/base/bytebuffer.h
index 8fd086367db88d8e6b6fe5e46ff7ded91b7e353a..cd7b2c6cea8e73231ce8fd43fef75bcd0f0f393f 100644
--- a/webrtc/base/bytebuffer.h
+++ b/webrtc/base/bytebuffer.h
@@ -57,6 +57,7 @@ class ByteBufferWriter : public ByteBuffer {
   void WriteUInt24(uint32_t val);
   void WriteUInt32(uint32_t val);
   void WriteUInt64(uint64_t val);
+  void WriteUVarint(uint64_t val);
   void WriteString(const std::string& val);
   void WriteBytes(const char* val, size_t len);
 
@@ -110,6 +111,7 @@ class ByteBufferReader : public ByteBuffer {
   bool ReadUInt24(uint32_t* val);
   bool ReadUInt32(uint32_t* val);
   bool ReadUInt64(uint64_t* val);
+  bool ReadUVarint(uint64_t* val);
   bool ReadBytes(char* val, size_t len);
 
   // Appends next |len| bytes from the buffer to |val|. Returns false