Mark Net.Certificate.ClientCertDialogCount.Android UMA obsolete

Bug: 1048210
Change-Id: Ia2ba09cf13fa0db4b6dc68a9d968028cc97831cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2081519Reviewed-by: Charlie Harrison <csharrison@chromium.org>
Reviewed-by: Dan McArdle <dmcardle@chromium.org>
Commit-Queue: Dan McArdle <dmcardle@chromium.org>
Cr-Commit-Position: refs/heads/master@{#746935}

chrome/browser/ui/android/ssl_client_certificate_request.cc

@@ -13,7 +13,6 @@
 #include "base/containers/queue.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
-#include "base/metrics/histogram_macros.h"
 #include "base/task/post_task.h"
 #include "chrome/android/chrome_jni_headers/SSLClientCertificateRequest_jni.h"
 #include "chrome/browser/ssl/ssl_client_certificate_selector.h"
@@ -103,20 +102,12 @@ class SSLClientCertPendingRequests
   void ReadyToCommitNavigation(
       content::NavigationHandle* navigation_handle) override;
 
-  void WebContentsDestroyed() override;
-
   class CertificateDialogPolicy {
    public:
     // Has the maximum number of cert dialogs been exceeded?
     bool MaxExceeded() { return count_ >= k_max_displayed_dialogs; }
     // Resets counter. Should be called on navigation.
-    void ResetCount() {
-      // Record sample right before the value is reset. This represents the
-      // maximum number of certificate dialogs displayed by sites in the wild.
-      UMA_HISTOGRAM_COUNTS_10000(
-          "Net.Certificate.ClientCertDialogCount.Android", count_);
-      count_ = 0;
-    }
+    void ResetCount() { count_ = 0; }
     // Increment the counter.
     void IncrementCount() { count_++; }
 
@@ -301,11 +292,6 @@ void SSLClientCertPendingRequests::ReadyToCommitNavigation(
   }
 }
 
-void SSLClientCertPendingRequests::WebContentsDestroyed() {
-  // Record UMA sample for last page loaded in WebContents.
-  dialog_policy_.ResetCount();
-}
-
 void ClientCertRequest::CertificateSelected(
     scoped_refptr<net::X509Certificate> cert,
     scoped_refptr<net::SSLPrivateKey> key) {

tools/metrics/histograms/histograms.xml

@@ -84208,6 +84208,10 @@ uploading your change for review.
 
 <histogram name="Net.Certificate.ClientCertDialogCount.Android" units="dialogs"
     expires_after="2020-03-14">
+  <obsolete>
+    Removed 03/2020, since the client cert dialog capping logic has been in
+    place for a year now without any problems.
+  </obsolete>
   <owner>dmcardle@chromium.org</owner>
   <owner>davidben@chromium.org</owner>
   <summary>