Add histograms that monitor variation seed fetching from Java.

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 eb8586f019806d160e79741f655792c4a79422c8..e6c8195292dc4e826f215e195efc98109b17b497 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -67664,6 +67664,24 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Variations.FirstRun.SeedFetchResult"
+    enum="VariationsFirstRunSeedFetchResult">
+  <owner>asvitkine@chromium.org</owner>
+  <summary>
+    The result of attempting to fetch an initial variations seed during Android
+    Chrome first run. Records both the HTTP code and various error values in one
+    enumeration.
+  </summary>
+</histogram>
+
+<histogram name="Variations.FirstRun.SeedFetchTime" units="ms">
+  <owner>asvitkine@chromium.org</owner>
+  <summary>
+    The latency of a fetching an initial variations seed during Android Chrome

[rkaplow, 2016/10/20 17:32:55]

remove 'a'

[Alexei Svitkine (slow), 2016/10/20 17:35:29]

Done.

+    first run. Only considers cases where an HTTP 200 result was received.
+  </summary>
+</histogram>
+
 <histogram name="Variations.FirstRunResult" enum="VariationsFirstRunResult">
   <owner>asvitkine@chromium.org</owner>
   <summary>
@@ -101902,6 +101920,50 @@ value.
   <int value="3" label="Seed import failed - failed to store seed"/>
 </enum>
 
+<enum name="VariationsFirstRunSeedFetchResult" type="int">
+  <int value="-2" label="Timeout fetching seed"/>
+  <int value="-1" label="IOException fetching seed"/>
+  <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="502" label="502: Bad Gateway"/>
+  <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="VariationsPermanentConsistencyCountryResult" type="int">
   <int value="0" label="Saved pref missing and no country code in seed"/>
   <int value="1" label="Saved pref missing and country code in seed"/>