Delete always-zero ByteBufferWriter::start_.

webrtc/base/bytebuffer.h

Index: webrtc/base/bytebuffer.h
diff --git a/webrtc/base/bytebuffer.h b/webrtc/base/bytebuffer.h
index cd7b2c6cea8e73231ce8fd43fef75bcd0f0f393f..546c4478154816c6f928745a6520425a7377b1f9 100644
--- a/webrtc/base/bytebuffer.h
+++ b/webrtc/base/bytebuffer.h
@@ -46,9 +46,9 @@ class ByteBufferWriter : public ByteBuffer {
 
   ~ByteBufferWriter();
 
-  const char* Data() const { return bytes_ + start_; }
-  size_t Length() const { return end_ - start_; }
-  size_t Capacity() const { return size_ - start_; }
+  const char* Data() const { return bytes_; }
+  size_t Length() const { return end_; }
+  size_t Capacity() const { return size_; }
 
   // Write value to the buffer. Resizes the buffer when it is
   // neccessary.
@@ -77,7 +77,6 @@ class ByteBufferWriter : public ByteBuffer {
 
   char* bytes_;
   size_t size_;
-  size_t start_;
   size_t end_;
 
   // There are sensible ways to define these, but they aren't needed in our code