Revert "QUIC - check for null stream_ before calling stream_'s IsDoneReading"

net/quic/quic_http_stream.cc

Index: net/quic/quic_http_stream.cc
diff --git a/net/quic/quic_http_stream.cc b/net/quic/quic_http_stream.cc
index 196d8e961196fd1a6fe0ccbb59f81090b9cad61a..db671f22e925e3313ae37f648a0e7e762eac4f1b 100644
--- a/net/quic/quic_http_stream.cc
+++ b/net/quic/quic_http_stream.cc
@@ -557,13 +557,6 @@ int QuicHttpStream::ProcessResponseHeaders(const SpdyHeaderBlock& headers) {
 
 int QuicHttpStream::ReadAvailableData(IOBuffer* buf, int buf_len) {
   int rv = stream_->Read(buf, buf_len);
-  // TODO(rtenneti): Temporary fix for crbug.com/585591. Added a check for null
-  // |stream_| to fix crash bug. Delete |stream_| check and histogram after fix
-  // is merged.
-  bool null_stream = stream_ == nullptr;
-  UMA_HISTOGRAM_BOOLEAN("Net.QuicReadAvailableData.NullStream", null_stream);
-  if (null_stream)
-    return rv;
   if (stream_->IsDoneReading()) {
     stream_->SetDelegate(nullptr);
     stream_->OnFinRead();