Mark WebFont.Resource.* histograms as obsolete

No longer tracked after Blink r162391.

BUG=246492
NOTRY=true

Review URL: https://codereview.chromium.org/400913002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284136 0039d316-1c4b-4281-b951-d872f2087c98

tools/metrics/histograms/histograms.xml

@@ -34692,6 +34692,9 @@ Therefore, the affected-histogram name has to have at least one dot in it.
 
 <histogram name="WebFont.Resource.StyleRecalcToDownloadLatency"
     units="milliseconds">
+  <obsolete>
+    Deprecated 11/2013. No longer tracked.
+  </obsolete>
   <owner>kenjibaheux@chromium.org</owner>
   <owner>ksakamoto@chromium.org</owner>
   <summary>
@@ -34703,6 +34706,9 @@ Therefore, the affected-histogram name has to have at least one dot in it.
 </histogram>
 
 <histogram name="WebFont.Resource.UsageType" enum="WebFontUsageType">
+  <obsolete>
+    Deprecated 11/2013. No longer tracked.
+  </obsolete>
   <owner>kenjibaheux@chromium.org</owner>
   <owner>ksakamoto@chromium.org</owner>
   <summary>