Enable spare RenderProcessHost to be preinitialized.

tools/metrics/histograms/enums.xml

Index: tools/metrics/histograms/enums.xml
diff --git a/tools/metrics/histograms/enums.xml b/tools/metrics/histograms/enums.xml
index 0c8a96417a871e2fb5eaf85ed9c2a5bf60503843..b2b4277e15029553be6d1ac55bd333702c9398e0 100644
--- a/tools/metrics/histograms/enums.xml
+++ b/tools/metrics/histograms/enums.xml
@@ -22326,17 +22326,6 @@ uploading your change for review.  These are checked by presubmit scripts.
 </enum>
 
 <enum name="LoginCustomFlags">
-<!--
-Values in LoginCustomFlags are:  value=(uint32_t)MD5(label).
-This enum is verified by AboutFlagsHistogramTest unit test.
-To add a new entry, add it with any unique value and run test to compute valid
-value. After that run tools/metrics/histograms/validate_format.py to find out
-where the value should be inserted to maintain ordering.
-Don't remove entries when removing a flag, they are still used to decode data
-from previous Chrome versions.
--->
-
-  <summary>Chrome flags that lead to Chrome restart on Chrome OS.</summary>
   <int value="-2146613579" label="V8Future:disabled"/>
   <int value="-2143961262" label="D3DVsync:disabled"/>
   <int value="-2143328006"
@@ -22991,6 +22980,17 @@ from previous Chrome versions.
   <int value="0" label="BAD_FLAG_FORMAT">
     Command-line flag doesn't start with two dashes.
   </int>
+<!--
+Values in LoginCustomFlags are:  value=(uint32_t)MD5(label).
+This enum is verified by AboutFlagsHistogramTest unit test.
+To add a new entry, add it with any unique value and run test to compute valid
+value. After that run tools/metrics/histograms/validate_format.py to find out
+where the value should be inserted to maintain ordering.
+Don't remove entries when removing a flag, they are still used to decode data
+from previous Chrome versions.
+-->
+
+  <summary>Chrome flags that lead to Chrome restart on Chrome OS.</summary>
   <int value="7444737" label="NTPSuggestionsStandaloneUI:disabled"/>
   <int value="7533886" label="disable-offer-store-unmasked-wallet-cards"/>
   <int value="10458238" label="disable-print-preview-simplify"/>
@@ -23170,6 +23170,7 @@ from previous Chrome versions.
   <int value="646738320" label="disable-gesture-editing"/>
   <int value="651421878" label="VideoRotateToFullscreen:enabled"/>
   <int value="652561231" label="CustomContextMenu:enabled"/>
+  <int value="655965118" label="OmniboxSpareRenderer"/>
   <int value="683410401"
       label="enable-proximity-auth-bluetooth-low-energy-discovery"/>
   <int value="684806628" label="TranslateLanguageByULP:disabled"/>