Upstream Chrome on iOS source code [1/11].

ios/chrome/app/application_delegate/background_activity.mm

+// Copyright 2016 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.
+
+#import "ios/chrome/app/application_delegate/background_activity.h"
+
+#import "base/ios/weak_nsobject.h"
+#include "base/metrics/histogram_macros.h"
+#include "base/metrics/user_metrics.h"
+#include "base/metrics/user_metrics_action.h"
+#include "base/time/time.h"
+#import "ios/chrome/app/application_delegate/browser_launcher.h"
+#import "ios/chrome/app/application_delegate/metrics_mediator.h"
+#import "ios/chrome/browser/crash_report/crash_report_background_uploader.h"
+#include "ios/chrome/browser/metrics/first_user_action_recorder.h"
+#import "ios/chrome/browser/metrics/previous_session_info.h"
+#include "url/gurl.h"
+
+namespace {
+// Key of the UMA Startup.BackgroundFetchTimeInterval histogram.
+const char* const kUMAMobileBackgroundFetchTimeInterval =
+    "Startup.BackgroundFetchTimeInterval";
+// Key in the UserDefaults to store the date/time that the application was last
+// launched for a background fetch.
+NSString* const kLastBackgroundFetch = @"LastBackgroundFetch";
+}  // namespace
+
+@implementation BackgroundActivity
+
+- (instancetype)init {
+  NOTREACHED();
+  return nil;
+}
+
+#pragma mark - Public class methods.
+
++ (void)application:(UIApplication*)application
+    performFetchWithCompletionHandler:
+        (void (^)(UIBackgroundFetchResult))completionHandler
+                      metricsMediator:(MetricsMediator*)metricsMediator
+                      browserLauncher:(id<BrowserLauncher>)browserLauncher {
+  [browserLauncher startUpBrowserToStage:INITIALIZATION_STAGE_BACKGROUND];
+
+  // TODO(crbug.com/616436): Check if this can be moved to MetricsMediator.
+  base::RecordAction(base::UserMetricsAction("BackgroundFetchCalled"));
+  NSUserDefaults* userDefaults = [NSUserDefaults standardUserDefaults];
+  base::Time lastTime =
+      base::Time::FromDoubleT([userDefaults doubleForKey:kLastBackgroundFetch]);
+  base::Time now = base::Time::Now();
+  if (!lastTime.is_null()) {
+    UMA_HISTOGRAM_LONG_TIMES_100(kUMAMobileBackgroundFetchTimeInterval,
+                                 now - lastTime);
+  }
+  [userDefaults setDouble:now.ToDoubleT() forKey:kLastBackgroundFetch];
+
+  // The crashes concerning an old version are obsolete. To reduce data usage,
+  // these crash reports are not uploaded.
+  if (![metricsMediator areMetricsEnabled] ||
+      [[PreviousSessionInfo sharedInstance] isFirstSessionAfterUpgrade]) {
+    [application setMinimumBackgroundFetchInterval:
+                     UIApplicationBackgroundFetchIntervalNever];
+    completionHandler(UIBackgroundFetchResultNoData);
+    return;
+  }
+
+  if (![metricsMediator isUploadingEnabled]) {
+    completionHandler(UIBackgroundFetchResultFailed);
+    return;
+  }
+  [CrashReportBackgroundUploader
+      performFetchWithCompletionHandler:completionHandler];
+}
+
++ (void)handleEventsForBackgroundURLSession:(NSString*)identifier
+                          completionHandler:(void (^)(void))completionHandler
+                            browserLauncher:
+                                (id<BrowserLauncher>)browserLauncher {
+  [browserLauncher startUpBrowserToStage:INITIALIZATION_STAGE_BACKGROUND];
+  if ([CrashReportBackgroundUploader
+          canHandleBackgroundURLSession:identifier]) {
+    [CrashReportBackgroundUploader
+        handleEventsForBackgroundURLSession:identifier
+                          completionHandler:completionHandler];
+  } else {
+    completionHandler();
+  }
+}
+
++ (void)foregroundStarted {
+  [[NSUserDefaults standardUserDefaults]
+      removeObjectForKey:kLastBackgroundFetch];
+}
+
+@end