Add new certificateProvider extension API.

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 0596909634f63d735965d6a0df5c045a03e009e9..c27f0f004d612943d8ef06c8305c134fa73d6faa 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -57414,6 +57414,8 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="381" label="CAST_DEVICES_PRIVATE_ON_UPDATE_DEVICES_REQUESTED"/>
   <int value="382" label="CAST_DEVICES_PRIVATE_ON_START_CAST"/>
   <int value="383" label="CAST_DEVICES_PRIVATE_ON_STOP_CAST"/>
+  <int value="384" label="CERTIFICATEPROVIDER_ON_CERTIFICATES_REQUESTED"/>
+  <int value="385" label="CERTIFICATEPROVIDER_ON_SIGN_DIGEST_REQUESTED"/>
 </enum>
 
 <enum name="ExtensionFileWriteResult" type="int">
@@ -58536,6 +58538,8 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="1076" label="SYSTEM_DISPLAY_ENABLEUNIFIEDDESKTOP"/>
   <int value="1077" label="BROWSINGDATA_REMOVECACHESTORAGE"/>
   <int value="1078" label="VIRTUALKEYBOARDPRIVATE_SETKEYBOARDSTATE"/>
+  <int value="1079" label="CERTIFICATEPROVIDERINTERNAL_REPORTSIGNATURE"/>
+  <int value="1080" label="CERTIFICATEPROVIDERINTERNAL_REPORTCERTIFICATES"/>
 </enum>
 
 <enum name="ExtensionInstallCause" type="int">