Implement permission embargo suppression metrics.

chrome/browser/permissions/permission_util.h

Index: chrome/browser/permissions/permission_util.h
diff --git a/chrome/browser/permissions/permission_util.h b/chrome/browser/permissions/permission_util.h
index 097203a73345aad369e072417c4a6caf2b399550..3f7c14c370c006a60c95e46e6098387d655914fa 100644
--- a/chrome/browser/permissions/permission_util.h
+++ b/chrome/browser/permissions/permission_util.h
@@ -35,6 +35,33 @@ enum PermissionAction {
   PERMISSION_ACTION_NUM,
 };
 
+// Identifies the source or reason for a permission status being returned. This
+// enum backs an UMA histogram and must be treated as append-only.
+enum class PermissionStatusSource {
+  // The reason for the status is not specified.
+  UNSPECIFIED,
+
+  // The status is the result of being blocked due to the user dismissing a
+  // permission prompt multiple times.
+  MULTIPLE_DISMISSALS,
+
+  // The status is the result of being blocked because the permission is on the
+  // safe browsing blacklist.
+  SAFE_BROWSING_BLACKLIST,
+
+  // The status is the result of being blocked by the permissions kill switch.
+  KILL_SWITCH,
+};
+
+struct PermissionResult {
+  PermissionResult(ContentSetting content_setting,
+                   PermissionStatusSource source);
+  ~PermissionResult();
+
+  ContentSetting content_setting;
+  PermissionStatusSource source;
+};
+
 // A utility class for permissions.
 class PermissionUtil {
  public: