Extend webRequest histograms until M73

These are about to expire, and we will probably want to collect data for
a little longer.

Bug: 904568
Change-Id: I9ebe814cd5ebe5de3dec10eca3efedb2c7bb94bb
Reviewed-on: https://chromium-review.googlesource.com/c/1351586Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611183}

tools/metrics/histograms/histograms.xml

@@ -34030,7 +34030,7 @@ uploading your change for review.
 </histogram>
 
 <histogram name="Extensions.WebRequest.SetCookieResponseHeaderChanged"
-    enum="BooleanChanged" expires_after="M72">
+    enum="BooleanChanged" expires_after="M73">
   <owner>cduvall@chromium.org</owner>
   <owner>karandeepb@chromium.org</owner>
   <summary>
@@ -34040,12 +34040,12 @@ uploading your change for review.
     onHeadersReceived events.
 
     This histogram is temporary, for investigating https://crbug.com/827582. It
-    can probably be removed by M72.
+    can probably be removed by M73.
   </summary>
 </histogram>
 
 <histogram name="Extensions.WebRequest.SetCookieResponseHeaderRemoved"
-    enum="BooleanRemoved" expires_after="M72">
+    enum="BooleanRemoved" expires_after="M73">
   <owner>cduvall@chromium.org</owner>
   <owner>karandeepb@chromium.org</owner>
   <summary>
@@ -34055,7 +34055,7 @@ uploading your change for review.
     onHeadersReceived events.
 
     This histogram is temporary, for investigating https://crbug.com/827582. It
-    can probably be removed by M72.
+    can probably be removed by M73.
   </summary>
 </histogram>
 
@@ -34077,7 +34077,7 @@ uploading your change for review.
 </histogram>
 
 <histogram name="Extensions.WebRequest.SpecialRequestHeadersChanged"
-    enum="WebRequestSpecialRequestHeaderModification" expires_after="M72">
+    enum="WebRequestSpecialRequestHeaderModification" expires_after="M73">
   <owner>cduvall@chromium.org</owner>
   <owner>karandeepb@chromium.org</owner>
   <summary>
@@ -34088,12 +34088,12 @@ uploading your change for review.
     onBeforeSendHeaders events.
 
     This histogram is temporary, for investigating https://crbug.com/827582. It
-    can probably be removed by M72.
+    can probably be removed by M73.
   </summary>
 </histogram>
 
 <histogram name="Extensions.WebRequest.SpecialRequestHeadersRemoved"
-    enum="WebRequestSpecialRequestHeaderModification" expires_after="M72">
+    enum="WebRequestSpecialRequestHeaderModification" expires_after="M73">
   <owner>cduvall@chromium.org</owner>
   <owner>karandeepb@chromium.org</owner>
   <summary>
@@ -34104,7 +34104,7 @@ uploading your change for review.
     onBeforeSendHeaders events.
 
     This histogram is temporary, for investigating https://crbug.com/827582. It
-    can probably be removed by M72.
+    can probably be removed by M73.
   </summary>
 </histogram>