Add UMA metric for GetHash parsing errors.

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 9483803bb475e69cc4479f85ba377ac320056dba..6f9de896954a83c2c5e2c3a299f4c8076e6b39db 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -40286,6 +40286,17 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="SafeBrowsing.ParseV4HashResult"
+    enum="SafeBrowsingParseV4HashResult">
+  <owner>kcarattini@chromium.org</owner>
+  <summary>
+    Track the parsing results of a status 200 GetV4Hash request
+    (PARSE_FROM_STRING_ERROR, UNEXPECTED_THREAT_ENTRY_TYPE_ERROR,

[Nathan Parker, 2016/01/20 23:09:58]

You don't need to list the enum values here, esp since this may get out of sync
with the list.

[kcarattini, 2016/01/20 23:23:39]

Done.

+    UNEXPECTED_THREAT_TYPE_ERROR, UNEXPECTED_PLATFORM_TYPE_ERROR,
+    NO_METADATA_ERROR).
+  </summary>
+</histogram>
+
 <histogram name="SafeBrowsing.Pref.Extended" enum="BooleanEnabled">
   <owner>nparker@chromium.org</owner>
   <summary>
@@ -75634,6 +75645,14 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="1" label="Kill (He's dead, Jim!)"/>
 </enum>
 
+<enum name="SafeBrowsingParseV4HashResult" type="int">
+  <int value="0" label="PARSE_FROM_STRING_ERROR"/>
+  <int value="1" label="UNEXPECTED_THREAT_ENTRY_TYPE_ERROR"/>
+  <int value="2" label="UNEXPECTED_THREAT_TYPE_ERROR"/>
+  <int value="3" label="UNEXPECTED_PLATFORM_TYPE_ERROR"/>
+  <int value="4" label="NO_METADATA_ERROR"/>
+</enum>
+
 <enum name="SavePasswordPromptResponseType" type="int">
   <int value="0" label="NO_RESPONSE"/>
   <int value="1" label="REMEMBER_PASSWORD"/>