Revert "Adds UMA to measure when the data reduction proxy via header is missing"

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 f30a994829901cf3b92898ca703e82538b109930..92112143d135f7434cc40bb90f20e4aef1825a81 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -3582,27 +3582,6 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
-<histogram name="DataReductionProxy.MissingViaHeader.Bytes" units="bytes">
-  <owner>bengr@chromium.org</owner>
-  <owner>sclittle@chromium.org</owner>
-  <summary>
-    Counts the response bytes of responses that Chrome expected to come through
-    a data reduction proxy and have the data reduction proxy via header, but
-    where the data reduction proxy via header was missing. Note that this does
-    not include responses that were bypassed.
-  </summary>
-</histogram>
-
-<histogram name="DataReductionProxy.MissingViaHeader.ResponseCode">
-  <owner>bengr@chromium.org</owner>
-  <owner>sclittle@chromium.org</owner>
-  <summary>
-    Counts the different HTTP response codes of responses that Chrome expected
-    to come through a data reduction proxy and have the data reduction proxy via
-    header, but where the data reduction proxy via header was missing.
-  </summary>
-</histogram>
-
 <histogram name="DataReductionProxy.NetworkChangeEvents"
     enum="DataReductionProxyNetworkChangeEvent">
   <owner>bengr@chromium.org</owner>
@@ -53141,20 +53120,6 @@ To add a new entry, add it with any value and run test to compute valid value.
   <affected-histogram name="DataReductionProxy.BypassedBytes"/>
 </histogram_suffixes>
 
-<histogram_suffixes name="DataReductionProxyMissingViaHeaderBytes"
-    separator=".">
-  <suffix name="4xx" label="Response with 4xx response code"/>
-  <suffix name="Other" label="Other response"/>
-  <affected-histogram name="DataReductionProxy.MissingViaHeader.Bytes"/>
-</histogram_suffixes>
-
-<histogram_suffixes name="DataReductionProxyMissingViaHeaderResponseCode"
-    separator=".">
-  <suffix name="Primary" label="Primary data reduction proxy"/>
-  <suffix name="Fallback" label="Fallback data reduction proxy"/>
-  <affected-histogram name="DataReductionProxy.MissingViaHeader.ResponseCode"/>
-</histogram_suffixes>
-
 <histogram_suffixes name="DefaultAppsExperiment">
   <suffix name="NoDefaultApps" label="User's without default apps installed"/>
   <suffix name="WithDefaultApps" label="User's with default apps installed"/>