Add a new UMA to GCM

components/gcm_driver/gcm_driver_desktop.cc

 // 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 "components/gcm_driver/gcm_driver_desktop.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/files/file_path.h"
 #include "base/location.h"
 #include "base/logging.h"
+#include "base/metrics/histogram.h"
 #include "base/sequenced_task_runner.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "components/gcm_driver/gcm_app_handler.h"
 #include "components/gcm_driver/gcm_channel_status_syncer.h"
 #include "components/gcm_driver/gcm_client_factory.h"
 #include "components/gcm_driver/gcm_delayed_task_controller.h"
 #include "components/gcm_driver/system_encryptor.h"
 #include "google_apis/gcm/engine/account_mapping.h"
 #include "net/base/ip_endpoint.h"
 #include "net/url_request/url_request_context_getter.h"
@@ skipping 618 matching lines @@
     return GCMClient::NOT_SIGNED_IN;
 
   DCHECK(!delayed_task_controller_);
   delayed_task_controller_.reset(new GCMDelayedTaskController);
 
   // Polling for channel status is only needed when GCM is supported for all
   // users.
   if (GCMDriver::IsAllowedForAllUsers())
     gcm_channel_status_syncer_->EnsureStarted();
 
+  UMA_HISTOGRAM_BOOLEAN("GCM.UserSignedIn", signed_in_);
+
   // Note that we need to pass weak pointer again since the existing weak
   // pointer in IOWorker might have been invalidated when check-out occurs.
   io_thread_->PostTask(
       FROM_HERE,
       base::Bind(&GCMDriverDesktop::IOWorker::Start,
                  base::Unretained(io_worker_.get()),
                  weak_ptr_factory_.GetWeakPtr()));
 
   gcm_started_ = true;
   return GCMClient::SUCCESS;
@@ skipping 95 matching lines @@
 
   // Normally request_gcm_statistics_callback_ would not be null.
   if (!request_gcm_statistics_callback_.is_null())
     request_gcm_statistics_callback_.Run(stats);
   else
     LOG(WARNING) << "request_gcm_statistics_callback_ is NULL.";
 }
 
 }  // namespace gcm