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

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 26ee511ba5312ab63ac815234c39327932f27d42..f11f237a96953cdd3cf1dbae24255e4cce1494da 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -26109,14 +26109,6 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
-<histogram name="Net.QuicReadAvailableData.NullStream" enum="BooleanNullStream">
-  <owner>rtenneti@chromium.org</owner>
-  <summary>
-    The number of times QuicHttpStream's stream_ is a nullptr before
-    IsDoneReading() is called.
-  </summary>
-</histogram>
-
 <histogram name="Net.QuicServerInfo.DiskCacheLoadTime" units="ms">
   <owner>rtenneti@chromium.org</owner>
   <summary>Time spent to load QUIC server information from disk cache.</summary>
@@ -58952,11 +58944,6 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="1" label="Missing data in disk cache"/>
 </enum>
 
-<enum name="BooleanNullStream" type="int">
-  <int value="0" label="Stream is not a nullptr"/>
-  <int value="1" label="Stream is a nullptr"/>
-</enum>
-
 <enum name="BooleanNullVisitor" type="int">
   <int value="0" label="Connection's visitor is not a nullptr"/>
   <int value="1" label="Connection's visitor is a nullptr"/>