Remove ChildProcess.HangRendererType.

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 51bb6cde7952b94be670036f1ec520ec8f27d76d..42955ebcc2eadd3f827ab861be84bbf75be3c25b 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -6605,6 +6605,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="ChildProcess.HangRendererType" enum="RendererUnresponsiveType">
+  <obsolete>
+    Deprecated 3/2017.
+  </obsolete>
   <owner>clamy@chromium.org</owner>
   <summary>
     What the browser was waiting for from the renderer when it was reported as
@@ -106780,12 +106783,15 @@ from previous Chrome versions.
 </enum>
 
 <enum name="RendererUnresponsiveType" type="int">
+  <obsolete>
+    Deprecated 3/2017.
+  </obsolete>
   <int value="0" label="Unknown"/>
   <int value="1" label="Pending in-flight events"/>
   <int value="2" label="Waiting for dialog closed"/>
   <int value="3" label="Suppressed dialogs in unload events"/>
   <int value="4" label="During BeforeUnload"/>
-  <int value="5" label="During Unload (obsolete)"/>
+  <int value="5" label="During Unload"/>
   <int value="6" label="While closing the page"/>
 </enum>