Implement newly designed sign-in related histograms for desktop platorms.

chrome/browser/ui/cocoa/profiles/user_manager_mac.mm

 // 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.
 
 #include "chrome/browser/ui/cocoa/profiles/user_manager_mac.h"
 
 #include "base/mac/foundation_util.h"
 #include "chrome/app/chrome_command_ids.h"
 #import "chrome/browser/app_controller_mac.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 201 matching lines @@
     auto closeButton = [window standardWindowButton:NSWindowCloseButton];
     [closeButton setTarget:self];
     [closeButton setAction:@selector(closeButtonClicked:)];
     [self show];
   }
 
   return self;
 }
 
 - (void)show {
-  GURL url = signin::GetReauthURLWithEmail(emailAddress_);
+  GURL url = signin::GetReauthURLWithEmail(
+      signin_metrics::AccessPoint::ACCESS_POINT_USER_MANAGER,
+      signin_metrics::Reason::REASON_UNLOCK, emailAddress_);
   reauthWebContents_->GetController().LoadURL(url, content::Referrer(),
                                         ui::PAGE_TRANSITION_AUTO_TOPLEVEL,
                                         std::string());
 }
 
 - (void)closeButtonClicked:(NSButton*)button {
   [self close];
 }
 
 - (void)close {
@@ skipping 239 matching lines @@
   ProfileMetrics::LogTimeToOpenUserManager(
       base::Time::Now() - user_manager_started_showing_);
   user_manager_started_showing_ = base::Time();
 }
 
 void UserManagerMac::WindowWasClosed() {
   CloseReauthDialog();
   instance_ = NULL;
   delete this;
 }