Mark various unused Safe Browsing histograms as deprecated.

Bug: 673607, 728827, 725336, 705809
Change-Id: Ia1418bba1f6ab0956637de3677a2f0fbef48adc9
Reviewed-on: https://chromium-review.googlesource.com/1233356Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Varun Khaneja <vakh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#593018}

tools/metrics/histograms/histograms.xml

@@ -87669,6 +87669,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.AddPrefixes">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>
     The number of add prefixes stored in the database after the last update.
@@ -87718,6 +87721,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.BuildFilter" units="ms">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>
     The time that it took to regenerate the filter after we have received all
@@ -87738,6 +87744,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.BuildReadKilobytes" units="KB">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>
     The number of kilobytes read by the browser process during the filter
@@ -87746,6 +87755,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.BuildReadOperations">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>
     The number of read operations issued by the browser process during the
@@ -87766,6 +87778,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.BuildWriteKilobytes" units="KB">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>
     The number of kilobytes written by the browser process during the filter
@@ -87774,6 +87789,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.BuildWriteOperations">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>
     The number of write operations issued by the browser process during the
@@ -87782,6 +87800,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.ChunkInsert" units="ms">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>
     The time that it takes to write one redirect URL (which can contain multiple
@@ -87790,6 +87811,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.ChunkRequest" units="ms">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>
     The network time between the request and response for a chunk.
@@ -87797,6 +87821,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.ChunkSize" units="bytes">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>The size of one chunk URL.</summary>
 </histogram>
@@ -87811,6 +87838,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.DatabaseFailure" enum="SB2DatabaseFailure">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>Track failures when updating the safe-browsing database.</summary>
 </histogram>
@@ -87826,6 +87856,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.DatabaseOpen" units="ms">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>
     The time it takes to initialize the SafeBrowsing storage backend, in
@@ -87834,6 +87867,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.DatabaseSizeKilobytes" units="KB">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>gab@chromium.org</owner>
   <summary>
     The size of one of the SafeBrowsing database file on disk in kilobytes,
@@ -87843,6 +87879,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.DatabaseUpdateKilobytes" units="KB">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>
     The size of the update file before merging with the database file, in
@@ -87927,6 +87966,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.DownloadHashCheckDuration" units="ms">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>
     The time it takes for SafeBrowsing to check hash of a download file.
@@ -87989,6 +88031,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.FilterLoad" enum="SB2FilterLoad">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>Which filter file the database loaded from disk.</summary>
 </histogram>
@@ -88036,6 +88081,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.FormatEvent" enum="SB2FormatEvent">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>
     Collection of boolean events for SafeBrowsingFileStore instances.  Includes
@@ -88045,6 +88093,9 @@ uploading your change for review.
 
 <histogram name="SB2.GetChunkResponseOrErrorCode"
     enum="CombinedHttpResponseAndNetErrorCode">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@google.com</owner>
   <summary>
     Response or error codes from the SafeBrowsing service. Logged after a
@@ -88084,6 +88135,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.GetHashResult" enum="SB2GetHashResult">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>mattm@chromium.org</owner>
   <summary>
     Track return status from GetHash attempts (STATUS_200, STATUS_204,
@@ -88098,6 +88152,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.GetHashResultDownload" enum="SB2GetHashResult">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>mattm@chromium.org</owner>
   <summary>
     Track return status from GetHash attempts (STATUS_200, STATUS_204,
@@ -88263,6 +88320,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.OutShardShifts">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>
     Indicates how sharded safe-browsing on-disk stores are.  Values like 0 to 4
@@ -88719,6 +88779,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="SB2.StoreVersionRead">
+  <obsolete>
+    Deprecated after the launch of PVer4 in M57.
+  </obsolete>
   <owner>vakh@chromium.org</owner>
   <summary>Version read from the store file.</summary>
 </histogram>