Remove Net.ProxyService.* histograms.

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 b80a3a814a7d054246f29c32bcd5f7aff3e3d8cd..d8614c3ab9cd9d73a3caec76331f667c9ec3d3da 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -38705,6 +38705,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 
 <histogram name="Net.ProxyService.GetProxyUsingScriptResult"
     enum="NetErrorCodes">
+  <obsolete>
+    Deprecated as of Chrome 61.
+  </obsolete>
   <owner>eroman@chromium.org</owner>
   <summary>
     The network error code of resolving a URL by forwarding the request to the
@@ -38714,6 +38717,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 
 <histogram name="Net.ProxyService.GetProxyUsingScriptTime"
     units="100s of microseconds">
+  <obsolete>
+    Deprecated as of Chrome 61.
+  </obsolete>
   <owner>eroman@chromium.org</owner>
   <summary>
     The time taken to resolve a URL by forwarding the request to the proxy
@@ -38724,6 +38730,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Net.ProxyService.ResolvedUsingScript" enum="Boolean">
+  <obsolete>
+    Deprecated as of Chrome 61.
+  </obsolete>
   <owner>eroman@chromium.org</owner>
   <summary>
     Whether proxy resolution occured by forwarding the request to the proxy
@@ -38739,6 +38748,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 
 <histogram name="Net.ProxyService.ResolveProxyTime"
     units="100s of microseconds">
+  <obsolete>
+    Deprecated as of Chrome 61.
+  </obsolete>
   <owner>eroman@chromium.org</owner>
   <summary>
     The total time taken to resolve a URL. This includes PAC script execution,
@@ -38748,6 +38760,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Net.ProxyService.ScriptTerminated" enum="BooleanTerminated">
+  <obsolete>
+    Deprecated as of Chrome 61.
+  </obsolete>
   <owner>eroman@chromium.org</owner>
   <summary>
     Whether a proxy resolution resulted in the PAC script terminating
@@ -38759,6 +38774,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 
 <histogram name="Net.ProxyService.ScriptTerminatedOnInit"
     enum="BooleanTerminated">
+  <obsolete>
+    Deprecated as of Chrome 61.
+  </obsolete>
   <owner>eroman@chromium.org</owner>
   <summary>
     Whether the creation of a new proxy resolver resulted in the PAC script