v4_update_protocol_manager: Basic implementation with TODOs

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 33edbd3bab3aa72b40c95c125f5aae49f6016745..dac68ffe336e1b55a32c5685fed2769c5780d5a0 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -42450,7 +42450,7 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="SafeBrowsing.GetV4HashResult"
-    enum="SafeBrowsingGetV4HashResult">
+    enum="SafeBrowsingV4OperationResult">
   <owner>kcarattini@chromium.org</owner>
   <summary>
     Track return status from V4 GetHash attempts. The buckets of this histogram
@@ -42475,6 +42475,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="SafeBrowsing.ParseV4UpdateResult"
+    enum="SafeBrowsingParseV4UpdateResult">
+  <owner>vakh@chromium.org</owner>
+  <summary>
+    Track the parsing results of a status 200 GetV4Update request.
+  </summary>
+</histogram>
+
 <histogram name="SafeBrowsing.Pref.Extended" enum="BooleanEnabled">
   <owner>nparker@chromium.org</owner>
   <summary>
@@ -42540,6 +42548,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="SafeBrowsing.V4UpdateResult"
+    enum="SafeBrowsingV4OperationResult">
+  <owner>vakh@chromium.org</owner>
+  <summary>
+    Track return status from V4 update attempts. The buckets of this histogram
+    overlap, so the counts cannot be used as percentages.
+  </summary>
+</histogram>
+
 <histogram name="SB.BloomFilter" units="ms">
   <obsolete>
     Has not been generated for years (7/8/14).
@@ -79560,15 +79577,6 @@ 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="SafeBrowsingGetV4HashResult" type="int">
-  <int value="0" label="STATUS_200"/>
-  <int value="1" label="PARSE_ERROR (subset of STATUS_200)"/>
-  <int value="2" label="NETWORK_ERROR"/>
-  <int value="3" label="HTTP_ERROR"/>
-  <int value="4" label="BACKOFF_ERROR"/>
-  <int value="5" label="MIN_WAIT_DURATION_ERROR"/>
-</enum>
-
 <enum name="SafeBrowsingParseV4HashResult" type="int">
   <int value="0" label="PARSE_FROM_STRING_ERROR"/>
   <int value="1" label="UNEXPECTED_THREAT_ENTRY_TYPE_ERROR"/>
@@ -79578,6 +79586,24 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="5" label="INCONSISTENT_THREAT_TYPE_ERROR"/>
 </enum>
 
+<enum name="SafeBrowsingParseV4UpdateResult" type="int">
+  <int value="0" label="PARSE_FROM_STRING_ERROR"/>
+  <int value="1" label="NO_PLATFORM_TYPE_ERROR"/>
+  <int value="2" label="NO_THREAT_ENTRY_TYPE_ERROR"/>
+  <int value="3" label="NO_THREAT_TYPE_ERROR"/>
+  <int value="4" label="NO_STATE_ERROR"/>
+</enum>
+
+<enum name="SafeBrowsingV4OperationResult" type="int">
+  <int value="0" label="STATUS_200"/>
+  <int value="1" label="PARSE_ERROR (subset of STATUS_200)"/>
+  <int value="2" label="NETWORK_ERROR"/>
+  <int value="3" label="HTTP_ERROR"/>
+  <int value="4" label="BACKOFF_ERROR"/>
+  <int value="5" label="MIN_WAIT_DURATION_ERROR"/>
+  <int value="6" label="ALREADY_PENDING_ERROR"/>
+</enum>
+
 <enum name="SavePasswordPromptResponseType" type="int">
   <int value="0" label="NO_RESPONSE"/>
   <int value="1" label="REMEMBER_PASSWORD"/>