Deprecate CredentialRequestOptions.unmediated in favor mediation enum

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 7158e9a56bcc76b0b7c3f2788fd92cbd02e44627..4ffed3c351bd611b7319b07117da5ac33e319a43 100644
--- a/tools/metrics/histograms/enums.xml
+++ b/tools/metrics/histograms/enums.xml
@@ -13936,8 +13936,8 @@ uploading your change for review.  These are checked by presubmit scripts.
   <int value="958" label="BackspaceNavigatedBackAfterFormInteraction"/>
   <int value="959" label="CSPSourceWildcardWouldMatchExactHost"/>
   <int value="960" label="CredentialManagerGet"/>
-  <int value="961" label="CredentialManagerGetWithUI"/>
-  <int value="962" label="CredentialManagerGetWithoutUI"/>
+  <int value="961" label="CredentialManagerGetMediationOptional"/>
+  <int value="962" label="CredentialManagerGetMediationSilent"/>
   <int value="963" label="CredentialManagerStore"/>
   <int value="964" label="CredentialManagerRequireUserMediation"/>
   <int value="965" label="RequestAutocomplete"/>
@@ -14983,6 +14983,9 @@ uploading your change for review.  These are checked by presubmit scripts.
   <int value="1974" label="PostMessageOutgoingWouldBeBlockedByConnectSrc"/>
   <int value="1975" label="PostMessageIncomingWouldBeBlockedByConnectSrc"/>
   <int value="1976" label="PaymentRequestNetworkNameInSupportedMethods"/>
+  <int value="1977"
+      label="CredentialManagerCredentialRequestOptionsUnmediated"/>

[vasilii, 2017/05/18 12:34:04]

Is it ever used for counting?

[jdoerrie, 2017/05/18 14:57:25]

They way I understand it this file has a bijection with UseCounter.h. There we
need the entry to show the deprecation warning. Maybe this is used internally to
count how often the deprecated method is called?

[vasilii, 2017/05/18 16:16:12]

Acknowledged.

+  <int value="1978" label="CredentialManagerGetMediationRequired"/>
 </enum>
 
 <enum name="FeedbackSource" type="int">