Adding UMA for data reduction proxy page load size/savings

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 05f9123175e4faf3a3b54159d45cbff96178a853..de114c1891480ab6114748955a57eb9aaea35f34 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -43069,6 +43069,161 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram
+    name="PageLoad.Clients.DataReductionProxy.PageLoad.Experimental.Bytes.Network.CompressionRatio"
+    units="%">
+  <owner>bengr@chromium.org</owner>
+  <owner>ryansturm@chromium.org</owner>
+  <summary>
+    100 times the ratio of network bytes received to network bytes the user
+    would have seen without data reduction proxy (not including headers) in a
+    page load that had its main resource loaded through data reduction proxy.
+    Recorded as a percent if the data reduction proxy saved the user data.
+    Recorded per page load when the user navigates away, hides the tab, or
+    backgrounds the app.
+  </summary>
+</histogram>
+
+<histogram
+    name="PageLoad.Clients.DataReductionProxy.PageLoad.Experimental.Bytes.Network.Inflation"
+    units="KB">
+  <owner>bengr@chromium.org</owner>
+  <owner>ryansturm@chromium.org</owner>
+  <summary>
+    The number of network kilobytes (not including headers) that the data
+    reduction proxy inflated for the user in a page load that had its main
+    resource was loaded through data reduction proxy. Recorded per page load
+    when the user navigates away, hides the tab, or backgrounds the app.
+  </summary>
+</histogram>
+
+<histogram
+    name="PageLoad.Clients.DataReductionProxy.PageLoad.Experimental.Bytes.Network.InflationPercent"
+    units="%">
+  <owner>bengr@chromium.org</owner>
+  <owner>ryansturm@chromium.org</owner>
+  <summary>
+    The inflation in network kilobytes (not including headers) the user saw due
+    to using data reduction proxy in a page load that had its main resource was
+    loaded through data reduction proxy. Recorded as a percent when the user saw
+    inflated data. Recorded per page load when the user navigates away, hides
+    the tab, or backgrounds the app.
+  </summary>
+</histogram>
+
+<histogram
+    name="PageLoad.Clients.DataReductionProxy.PageLoad.Experimental.Bytes.Network.NonProxied"
+    units="KB">
+  <owner>bengr@chromium.org</owner>
+  <owner>ryansturm@chromium.org</owner>
+  <summary>
+    The number of network kilobytes that were not fetched through the data
+    reduction proxy (not including headers) in a page load that had its main
+    resource was loaded through data reduction proxy. Recorded per page load
+    when the user navigates away, hides the tab, or backgrounds the app.
+  </summary>
+</histogram>
+
+<histogram
+    name="PageLoad.Clients.DataReductionProxy.PageLoad.Experimental.Bytes.Network.Original"
+    units="KB">
+  <owner>bengr@chromium.org</owner>
+  <owner>ryansturm@chromium.org</owner>
+  <summary>
+    The number of network kilobytes (not including headers) that the user would
+    have seen without using data reduction proxy in a page load that had its
+    main resource was loaded through data reduction proxy. Recorded per page
+    load when the user navigates away, hides the tab, or backgrounds the app.
+  </summary>
+</histogram>
+
+<histogram
+    name="PageLoad.Clients.DataReductionProxy.PageLoad.Experimental.Bytes.Network.PercentProxied"
+    units="%">
+  <owner>bengr@chromium.org</owner>
+  <owner>ryansturm@chromium.org</owner>
+  <summary>
+    The percent of network kilobytes (not including headers) in a page load that
+    went through data reduction proxy when the main resource was loaded through
+    data reduction proxy. Recorded per page load when the user navigates away,
+    hides the tab, or backgrounds the app.
+  </summary>
+</histogram>
+
+<histogram
+    name="PageLoad.Clients.DataReductionProxy.PageLoad.Experimental.Bytes.Network.Proxied"
+    units="KB">
+  <owner>bengr@chromium.org</owner>
+  <owner>ryansturm@chromium.org</owner>
+  <summary>
+    The number of network kilobytes that were fetched through the data reduction
+    proxy (not including headers) in a page load that had its main resource was
+    loaded through data reduction proxy. Recorded per page load when the user
+    navigates away, hides the tab, or backgrounds the app.
+  </summary>
+</histogram>
+
+<histogram
+    name="PageLoad.Clients.DataReductionProxy.PageLoad.Experimental.Bytes.Network.Savings"
+    units="KB">
+  <owner>bengr@chromium.org</owner>
+  <owner>ryansturm@chromium.org</owner>
+  <summary>
+    The number of network kilobytes (not including headers) that the data
+    reduction proxy saved the user in a page load that had its main resource was
+    loaded through data reduction proxy. Recorded per page load when the user
+    navigates away, hides the tab, or backgrounds the app.
+  </summary>
+</histogram>
+
+<histogram
+    name="PageLoad.Clients.DataReductionProxy.PageLoad.Experimental.Requests.Network">
+  <owner>bengr@chromium.org</owner>
+  <owner>ryansturm@chromium.org</owner>
+  <summary>
+    The number of network requests in a page load when the main resource was
+    loaded through data reduction proxy. Recorded per page load when the user
+    navigates away, hides the tab, or backgrounds the app.
+  </summary>
+</histogram>
+
+<histogram
+    name="PageLoad.Clients.DataReductionProxy.PageLoad.Experimental.Requests.Network.NonProxied">
+  <owner>bengr@chromium.org</owner>
+  <owner>ryansturm@chromium.org</owner>
+  <summary>
+    The number of network requests in a page load that were not fetched through
+    the data reduction proxy when the main resource was loaded through data
+    reduction proxy. Recorded per page load when the user navigates away, hides
+    the tab, or backgrounds the app.
+  </summary>
+</histogram>
+
+<histogram
+    name="PageLoad.Clients.DataReductionProxy.PageLoad.Experimental.Requests.Network.PercentProxied"
+    units="%">
+  <owner>bengr@chromium.org</owner>
+  <owner>ryansturm@chromium.org</owner>
+  <summary>
+    The percent of network requests in a page load that use data reduction proxy
+    when the main resource was loaded through data reduction proxy. Recorded per
+    page load when the user navigates away, hides the tab, or backgrounds the
+    app.
+  </summary>
+</histogram>
+
+<histogram
+    name="PageLoad.Clients.DataReductionProxy.PageLoad.Experimental.Requests.Network.Proxied">

[Alexei Svitkine (slow), 2017/01/19 18:39:50]

Nit: add units="requests"

Also to the other ones that don't specify it.

[RyanSturm, 2017/01/19 19:32:45]

Done.

+  <owner>bengr@chromium.org</owner>
+  <owner>ryansturm@chromium.org</owner>
+  <summary>
+    The number of network requests in a page load that were fetched through the
+    data reduction proxy when the main resource was loaded through data
+    reduction proxy. Recorded per page load when the user navigates away, hides
+    the tab, or backgrounds the app.
+  </summary>
+</histogram>
+
 <histogram name="PageLoad.Clients.DocWrite.Block.Count" enum="Boolean">
   <owner>bmcquade@chromium.org</owner>
   <summary>
@@ -114888,6 +115043,7 @@ value.
   <affected-histogram name="PageLoad.DocumentTiming.NavigationToFirstLayout"/>
   <affected-histogram
       name="PageLoad.DocumentTiming.NavigationToLoadEventFired"/>
+  <affected-histogram name="PageLoad.Experimental.Bytes.Network"/>
   <affected-histogram
       name="PageLoad.Experimental.PaintTiming.NavigationToFirstMeaningfulPaint"/>
   <affected-histogram