Migrate H-L histograms to patterned histogram syntax

This is part of a migration that replaces the old
<histogram-suffixes> syntax that was used to denote groups
of histogram to the new patterned histogram syntax.

Bug: 758782
Change-Id: Ide054101bd01cb64d697106fb5ec85b88137c1bb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2476609Reviewed-by: Weilun Shi <sweilun@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Karthika Pai <karthikapai@google.com>
Cr-Commit-Position: refs/heads/master@{#819044}

tools/metrics/histograms/histograms_xml/histogram_suffixes_list.xml

@@ -7501,17 +7501,6 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   <affected-histogram name="InputMethod.Commit.Type"/>
 </histogram_suffixes>
 
-<histogram_suffixes name="IMEVKLatency" separator=".">
-  <suffix name="BackgroundSettingsFetched"
-      label="Latency for settings fetched from background"/>
-  <suffix name="HtmlLoaded" label="Latency for the page is loaded"/>
-  <suffix name="KeyboardCreated" label="Latency for the keyboard is created"/>
-  <suffix name="KeyboardShown" label="Latency for keyboard is shown"/>
-  <suffix name="KeysetLoaded" label="Latency for keyset config is loaded"/>
-  <suffix name="LayoutLoaded" label="Latency for layout definition is loaded"/>
-  <affected-histogram name="InputMethod.VirtualKeyboard.InitLatency"/>
-</histogram_suffixes>
-
 <histogram_suffixes name="ImmediatePageLoadTiming" separator=".">
   <obsolete>
     Removed by PageLoad.PaintTiming.NavigationToFirstContentfulPaint.
@@ -8495,15 +8484,6 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
       name="ResourceCoordinator.LocalDB.ObservationTimeBeforeFirstUse"/>
 </histogram_suffixes>
 
-<histogram_suffixes name="LocalStorageContextOpenReasons" separator="">
-  <suffix name="CommitErrors" label="After too many commit errors."/>
-  <suffix name="InvalidVersion" label="After an invalid version was read."/>
-  <suffix name="OpenFailed" label="After opening the DB failed."/>
-  <suffix name="ReadVersionError"
-      label="After reading the schema version failed."/>
-  <affected-histogram name="LocalStorageContext.OpenResultAfter"/>
-</histogram_suffixes>
-
 <histogram_suffixes name="LocationAttachedStatus" separator=".">
   <suffix name="LocationAttached"
       label="This histogram is for when the location was successfully

tools/metrics/histograms/histograms_xml/input/histograms.xml

@@ -596,15 +596,6 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
-<histogram name="InputMethod.VirtualKeyboard.InitLatency" units="ms"
-    expires_after="M95">
-  <owner>shend@chromium.org</owner>
-  <owner>essential-inputs-team@google.com</owner>
-  <summary>
-    The on-screen keyboard initialization latency in milliseconds.
-  </summary>
-</histogram>
-
 <histogram name="InputMethod.VirtualKeyboard.InitLatency.KeyboardShownLongTail"
     units="ms" expires_after="2021-03-28">
   <owner>jopalmer@chromium.org</owner>
@@ -616,6 +607,29 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
+<histogram name="InputMethod.VirtualKeyboard.InitLatency{IMEVKLatency}"
+    units="ms" expires_after="M95">
+  <owner>shend@chromium.org</owner>
+  <owner>essential-inputs-team@google.com</owner>
+  <summary>
+    The on-screen keyboard initialization latency in milliseconds.
+    {IMEVKLatency}
+  </summary>
+  <token key="IMEVKLatency">
+    <variant name=""/>
+    <variant name=".BackgroundSettingsFetched"
+        summary="Latency for settings fetched from background"/>
+    <variant name=".HtmlLoaded" summary="Latency for the page is loaded"/>
+    <variant name=".KeyboardCreated"
+        summary="Latency for the keyboard is created"/>
+    <variant name=".KeyboardShown" summary="Latency for keyboard is shown"/>
+    <variant name=".KeysetLoaded"
+        summary="Latency for keyset config is loaded"/>
+    <variant name=".LayoutLoaded"
+        summary="Latency for layout definition is loaded"/>
+  </token>
+</histogram>
+
 <histogram name="InputMethod.VirtualKeyboard.Layout" enum="IMEVKLayout"
     expires_after="M95">
   <owner>shend@chromium.org</owner>

tools/metrics/histograms/histograms_xml/local/histograms.xml

@@ -315,14 +315,27 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
-<histogram base="true" name="LocalStorageContext.OpenResultAfter"
+<histogram
+    name="LocalStorageContext.OpenResultAfter{LocalStorageContextOpenReasons}"
     enum="LocalStorageOpenError" expires_after="M87">
-<!-- Name completed by histogram_suffixes name="LocalStorageContextOpenReasons" -->
-
   <owner>mek@chromium.org</owner>
   <summary>
     The result of opening the LevelDB database that backs LocalStorage.
+    {LocalStorageContextOpenReasons}
   </summary>
+  <token key="LocalStorageContextOpenReasons">
+    <variant name="">
+      <obsolete>
+        Base histogram. Use suffixes of this histogram instead.
+      </obsolete>
+    </variant>
+    <variant name="CommitErrors" summary="After too many commit errors."/>
+    <variant name="InvalidVersion"
+        summary="After an invalid version was read."/>
+    <variant name="OpenFailed" summary="After opening the DB failed."/>
+    <variant name="ReadVersionError"
+        summary="After reading the schema version failed."/>
+  </token>
 </histogram>
 
 <histogram name="LocalStorageContext.ReadVersionError" enum="LevelDBStatus"