[Android] Adding UMA for events in Background Task Scheduler

components/background_task_scheduler/BUILD.gn

 # Copyright 2017 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.
 
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")
 }
 
 # Convenience target for developers to build prod and test code.
@@ skipping 13 matching lines @@
     java_files = [
       "android/java/src/org/chromium/components/background_task_scheduler/BackgroundTask.java",
       "android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskGcmTaskService.java",
       "android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskJobService.java",
       "android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskScheduler.java",
       "android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerDelegate.java",
       "android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerFactory.java",
       "android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerGcmNetworkManager.java",
       "android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerJobService.java",
       "android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerPrefs.java",
+      "android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerUma.java",
       "android/java/src/org/chromium/components/background_task_scheduler/BundleToPersistableBundleConverter.java",
       "android/java/src/org/chromium/components/background_task_scheduler/TaskIds.java",
       "android/java/src/org/chromium/components/background_task_scheduler/TaskInfo.java",
       "android/java/src/org/chromium/components/background_task_scheduler/TaskParameters.java",
     ]
 
     deps = [
       "//base:base_java",
       "//third_party/android_tools:android_support_annotations_java",
       google_play_services_library,
@@ skipping 17 matching lines @@
       google_play_services_library,
     ]
   }
 
   junit_binary("components_background_task_scheduler_junit_tests") {
     java_files = [
       "android/junit/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerGcmNetworkManagerTest.java",
       "android/junit/src/org/chromium/components/background_task_scheduler/BackgroundTaskGcmTaskServiceTest.java",
       "android/junit/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerPrefsTest.java",
       "android/junit/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerTest.java",
+      "android/junit/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerUmaTest.java",
       "android/junit/src/org/chromium/components/background_task_scheduler/ShadowGcmNetworkManager.java",
       "android/junit/src/org/chromium/components/background_task_scheduler/TestBackgroundTask.java",
     ]
 
     deps = [
       ":background_task_scheduler_java",
       "//base:base_java",
       "//base:base_java_test_support",
       "//third_party/junit",
       google_play_services_library,
     ]
     srcjar_deps = [ "//base:base_build_config_gen" ]
   }
 }