Add UMA for signin through NTP content suggestions.

components/signin/core/browser/signin_metrics.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_SIGNIN_CORE_BROWSER_SIGNIN_METRICS_H_
 #define COMPONENTS_SIGNIN_CORE_BROWSER_SIGNIN_METRICS_H_
 
 #include <limits.h>
 
 #include "base/time/time.h"
@@ skipping 121 matching lines @@
   ACCESS_POINT_AVATAR_BUBBLE_SIGN_IN,
   ACCESS_POINT_USER_MANAGER,
   ACCESS_POINT_DEVICES_PAGE,
   ACCESS_POINT_CLOUD_PRINT,
   ACCESS_POINT_CONTENT_AREA,
   ACCESS_POINT_SIGNIN_PROMO,
   ACCESS_POINT_RECENT_TABS,
   ACCESS_POINT_UNKNOWN,  // This should never have been used to get signin URL.
   ACCESS_POINT_PASSWORD_BUBBLE,
   ACCESS_POINT_AUTOFILL_DROPDOWN,
+  ACCESS_POINT_NTP_CONTENT_SUGGESTIONS,
   ACCESS_POINT_MAX,  // This must be last.
 };
 
 // Enum values which enumerates all reasons to start sign in process.
 // A Java counterpart will be generated for this enum.
 // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.chrome.browser.signin
 // GENERATED_JAVA_CLASS_NAME_OVERRIDE: SigninReason
 enum class Reason : int {
   REASON_SIGNIN_PRIMARY_ACCOUNT = 0,
   REASON_ADD_SECONDARY_ACCOUNT,
@@ skipping 251 matching lines @@
       UMA_HISTOGRAM_ENUMERATION(name "_Periodic", sample, boundary_value);     \
       break;                                                                   \
     case ReportingType::ON_CHANGE:                                             \
       UMA_HISTOGRAM_ENUMERATION(name "_OnChange", sample, boundary_value);     \
       break;                                                                   \
   }
 
 }  // namespace signin_metrics
 
 #endif  // COMPONENTS_SIGNIN_CORE_BROWSER_SIGNIN_METRICS_H_