UMA for data reduction proxy video percentages are being reported when users don't watch video.

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 2d9baf6a6298c609bde35a25ecc00b663439afda..f786c1a2f1d9e16c703bb9b8e7d8eebcc60a3856 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -25774,31 +25774,58 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <owner>bengr@chromium.org</owner>
   <owner>bolian@chromium.org</owner>
   <summary>
     The percentage of data saving in the previous calendar day while the data
     reduction proxy was enabled. A negative saving will be shown as zero. This
     only counts responses while the data reduction proxy is enabled. The metric
     is reported when the first response in the current day is received.
   </summary>
 </histogram>
 
+<histogram name="Net.DailyContentSavingPercent_DataReductionProxyEnabled_Video"
+    units="%">
+  <owner>bengr@chromium.org</owner>
+  <owner>bolian@chromium.org</owner>
+  <summary>
+    The percentage of data saving in the previous calendar day while the data
+    reduction proxy was enabled. A negative saving will be shown as zero. This
+    only counts responses while the data reduction proxy is enabled. The metric
+    is reported when the first response in the current day is received. If no
+    video bytes were received while the data reduction proxy was enabled, the
+    metric will not be reported.
+  </summary>
+</histogram>
+
 <histogram name="Net.DailyContentSavingPercent_ViaDataReductionProxy" units="%">
   <owner>bengr@chromium.org</owner>
   <owner>bolian@chromium.org</owner>
   <summary>
     The percentage of data saving in the previous calendar day via the data
     reduction proxy. A negative saving will be shown as zero. This only counts
     responses via the data reduction proxy. The metric is reported when the
     first response in the current day is received.
   </summary>
 </histogram>
 
+<histogram name="Net.DailyContentSavingPercent_ViaDataReductionProxy_Video"

[Alexei Svitkine (slow), 2016/05/06 21:37:03]

Why split these out? Is it because you don't want the other suffixes? If so, I'd
just create a new histogram_suffixes group with just Video as the single suffix.

[RyanSturm, 2016/05/06 21:51:03]

I actually want text specific to only these metrics in the summary. "If no video
bytes were received via the data reduction proxy" and "If no video bytes were
received while the data reduction proxy was enabled" are very specific and
necessary to convey the meaning of each metric.

+    units="%">
+  <owner>bengr@chromium.org</owner>
+  <owner>bolian@chromium.org</owner>
+  <summary>
+    The percentage of data saving in the previous calendar day via the data
+    reduction proxy. A negative saving will be shown as zero. This only counts
+    responses via the data reduction proxy. The metric is reported when the
+    first response in the current day is received. If no video bytes were
+    received via the data reduction proxy, the metric will not be reported.
+  </summary>
+</histogram>
+
 <histogram name="Net.DailyHttpContentLengthViaDataReductionProxy" units="KB">
   <obsolete>
     Deprecated- see Net.DailyContentLength_ViaDataReductionProxy.
   </obsolete>
   <owner>bolian@chromium.org</owner>
   <summary>
     Total size in KB of all response bodies in the previous calendar day that
     were received through the data reduction proxy.
   </summary>
 </histogram>
@@ -89973,24 +90000,20 @@ To add a new entry, add it with any value and run test to compute valid value.
 
 <histogram_suffixes name="DataReductionProxy.MimeType">
   <suffix name="Application" label="Application mime-type"/>
   <suffix name="Unknown"
       label="Deprecated. Moved to UnknownMime in M46. Unknown mime-type"/>
   <suffix name="UnknownMime" label="Unknown mime-type"/>
   <suffix name="Video" label="Video mime-type"/>
   <affected-histogram name="Net.DailyContentLength"/>
   <affected-histogram name="Net.DailyContentLength_DataReductionProxyEnabled"/>
   <affected-histogram name="Net.DailyContentLength_ViaDataReductionProxy"/>
-  <affected-histogram
-      name="Net.DailyContentSavingPercent_DataReductionProxyEnabled"/>
-  <affected-histogram
-      name="Net.DailyContentSavingPercent_ViaDataReductionProxy"/>
   <affected-histogram name="Net.DailyOriginalContentLength"/>
   <affected-histogram
       name="Net.DailyOriginalContentLength_DataReductionProxyEnabled"/>
   <affected-histogram
       name="Net.DailyOriginalContentLength_ViaDataReductionProxy"/>
 </histogram_suffixes>
 
 <histogram_suffixes name="DataReductionProxy.NetworkTypes" separator=".">
   <suffix name="Unknown" label="On Unknown network"/>
   <suffix name="Ethernet" label="On Ethernet network"/>