Make http result code histograms show the value too.

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 32777d90688db85e7775068b8d8204c56dd90cfc..30af99379d344a9f80dab6f26eddf56c6557e3c9 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -43875,46 +43875,46 @@ Therefore, the affected-histogram name has to have at least one dot in it.
 </enum>
 
 <enum name="HttpResponseCode" type="int">
-  <int value="100" label="Continue"/>
-  <int value="101" label="Switching Protocols"/>
-  <int value="200" label="OK"/>
-  <int value="201" label="Created"/>
-  <int value="202" label="Accepted"/>
-  <int value="203" label="Non-Authoritative Information"/>
-  <int value="204" label="No Content"/>
-  <int value="205" label="Reset Content"/>
-  <int value="206" label="Partial Content"/>
-  <int value="300" label="Multiple Choices"/>
-  <int value="301" label="Moved Permanently"/>
-  <int value="302" label="Found"/>
-  <int value="303" label="See Other"/>
-  <int value="304" label="Not Modified"/>
-  <int value="305" label="Use Proxy"/>
-  <int value="306" label="(Unused)"/>
-  <int value="307" label="Temporary Redirect"/>
-  <int value="400" label="Bad Request"/>
-  <int value="401" label="Unauthorized"/>
-  <int value="402" label="Payment Required"/>
-  <int value="403" label="Forbidden"/>
-  <int value="404" label="Not Found"/>
-  <int value="405" label="Method Not Allowed"/>
-  <int value="406" label="Not Acceptable"/>
-  <int value="407" label="Proxy Authentication Required"/>
-  <int value="408" label="Request Timeout"/>
-  <int value="409" label="Conflict"/>
-  <int value="410" label="Gone"/>
-  <int value="411" label="Length Required"/>
-  <int value="412" label="Precondition Failed"/>
-  <int value="413" label="Request Entity Too Large"/>
-  <int value="414" label="Request-URI Too Long"/>
-  <int value="415" label="Unsupported Media Type"/>
-  <int value="416" label="Requested Range Not Satisfiable"/>
-  <int value="417" label="Expectation Failed"/>
-  <int value="500" label="Internal Server Error"/>
-  <int value="501" label="Not Implemented"/>
-  <int value="503" label="Service Unavailable"/>
-  <int value="504" label="Gateway Timeout"/>
-  <int value="505" label="HTTP Version Not Supported"/>
+  <int value="100" label="100: Continue"/>
+  <int value="101" label="101: Switching Protocols"/>
+  <int value="200" label="200: OK"/>
+  <int value="201" label="201: Created"/>
+  <int value="202" label="202: Accepted"/>
+  <int value="203" label="203: Non-Authoritative Information"/>
+  <int value="204" label="204: No Content"/>
+  <int value="205" label="205: Reset Content"/>
+  <int value="206" label="206: Partial Content"/>
+  <int value="300" label="300: Multiple Choices"/>
+  <int value="301" label="301: Moved Permanently"/>
+  <int value="302" label="302: Found"/>
+  <int value="303" label="303: See Other"/>
+  <int value="304" label="304: Not Modified"/>
+  <int value="305" label="305: Use Proxy"/>
+  <int value="306" label="306: (Unused)"/>
+  <int value="307" label="307: Temporary Redirect"/>
+  <int value="400" label="400: Bad Request"/>
+  <int value="401" label="401: Unauthorized"/>
+  <int value="402" label="402: Payment Required"/>
+  <int value="403" label="403: Forbidden"/>
+  <int value="404" label="404: Not Found"/>
+  <int value="405" label="405: Method Not Allowed"/>
+  <int value="406" label="406: Not Acceptable"/>
+  <int value="407" label="407: Proxy Authentication Required"/>
+  <int value="408" label="408: Request Timeout"/>
+  <int value="409" label="409: Conflict"/>
+  <int value="410" label="410: Gone"/>
+  <int value="411" label="411: Length Required"/>
+  <int value="412" label="412: Precondition Failed"/>
+  <int value="413" label="413: Request Entity Too Large"/>
+  <int value="414" label="414: Request-URI Too Long"/>
+  <int value="415" label="415: Unsupported Media Type"/>
+  <int value="416" label="416: Requested Range Not Satisfiable"/>
+  <int value="417" label="417: Expectation Failed"/>
+  <int value="500" label="500: Internal Server Error"/>
+  <int value="501" label="501: Not Implemented"/>
+  <int value="503" label="503: Service Unavailable"/>
+  <int value="504" label="504: Gateway Timeout"/>
+  <int value="505" label="505: HTTP Version Not Supported"/>
 </enum>
 
 <enum name="HttpSocketType" type="int">