[iOS] Upstream crash loop detection utilities

BUG=429756

Review URL: https://codereview.chromium.org/1147703002

Cr-Commit-Position: refs/heads/master@{#330361}

ios/chrome/browser/crash_loop_detection_util.h

+// Copyright 2013 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 IOS_CHROME_BROWSER_CRASH_LOOP_DETECTION_UTIL_H_
+#define IOS_CHROME_BROWSER_CRASH_LOOP_DETECTION_UTIL_H_
+
+namespace crash_util {
+
+// Returns the number of consecutive failed startups ('instant' crashes) prior
+// to this one. This method always returns the number of prior failures even
+// after calls to increment or reset the value.
+int GetFailedStartupAttemptCount();
+
+// Increases the failed startup count. This should be called immediately after
+// startup, so that if there is a crash, it is recorded.
+// If |flush_immediately| is true, the value will be persisted immediately. If
+// |flush_immediately| is false, this should be followed by a call to
+// [[NSUserDefaults standardUserDefaults] synchronize]. This is optional to
+// allow coallescing of the potentially expensive call during startup.
+void IncrementFailedStartupAttemptCount(bool flush_immediately);
+
+// Resets the failed startup count. This should be called once there is some
+// indication the user isn't in a crash loop (e.g., some amount of time has
+// elapsed, or some deliberate user action has been taken).
+void ResetFailedStartupAttemptCount();
+
+}  // namespace crash_util
+
+#endif  // IOS_CHROME_BROWSER_CRASH_LOOP_DETECTION_UTIL_H_

ios/chrome/browser/crash_loop_detection_util.mm

+// Copyright 2013 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 "ios/chrome/browser/crash_loop_detection_util.h"
+
+#import <Foundation/Foundation.h>
+
+namespace {
+NSString* const kAppStartupFailureCountKey = @"AppStartupFailureCount";
+}
+
+namespace crash_util {
+
+int GetFailedStartupAttemptCount() {
+  static int startup_attempt_count = -1;
+  if (startup_attempt_count == -1) {
+    NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+    startup_attempt_count = [defaults integerForKey:kAppStartupFailureCountKey];
+  }
+  return startup_attempt_count;
+}
+
+void IncrementFailedStartupAttemptCount(bool flush_immediately) {
+  int startup_attempt_count = GetFailedStartupAttemptCount();
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  [defaults setInteger:(startup_attempt_count + 1)
+                forKey:kAppStartupFailureCountKey];
+  if (flush_immediately)
+    [defaults synchronize];
+}
+
+void ResetFailedStartupAttemptCount() {
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  if ([defaults integerForKey:kAppStartupFailureCountKey] != 0) {
+    [defaults setInteger:0 forKey:kAppStartupFailureCountKey];
+    [defaults synchronize];
+  }
+}
+
+}  // namespace crash_util

ios/chrome/browser/crash_loop_detection_util_unittest.mm

+// Copyright 2013 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 <Foundation/Foundation.h>
+
+#include "ios/chrome/browser/crash_loop_detection_util.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/platform_test.h"
+
+namespace {
+// The key used to store the count in the implementation.
+NSString* const kAppStartupAttemptCountKey = @"AppStartupFailureCount";
+
+typedef PlatformTest CrashLoopDetectionUtilTest;
+
+TEST_F(CrashLoopDetectionUtilTest, FullCycle) {
+  // Simulate one prior crash.
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  [defaults setInteger:1 forKey:kAppStartupAttemptCountKey];
+
+  EXPECT_EQ(1, crash_util::GetFailedStartupAttemptCount());
+
+  crash_util::IncrementFailedStartupAttemptCount(false);
+
+  // It should still report 1, since it's reporting failures prior to this
+  // launch.
+  EXPECT_EQ(1, crash_util::GetFailedStartupAttemptCount());
+  // ... but under the hood the value should now be 2.
+  EXPECT_EQ(2, [defaults integerForKey:kAppStartupAttemptCountKey]);
+
+  // If it's mistakenly incerement again, nothing should change.
+  crash_util::IncrementFailedStartupAttemptCount(false);
+  EXPECT_EQ(2, [defaults integerForKey:kAppStartupAttemptCountKey]);
+
+  // After a reset it should be 0 internally, but the same via the API.
+  crash_util::ResetFailedStartupAttemptCount();
+  EXPECT_EQ(1, crash_util::GetFailedStartupAttemptCount());
+  EXPECT_EQ(0, [defaults integerForKey:kAppStartupAttemptCountKey]);
+}
+
+}  // namespace

ios/chrome/ios_chrome.gyp

@@ -122,6 +122,8 @@
         'browser/chrome_url_constants.h',
         'browser/chrome_url_util.h',
         'browser/chrome_url_util.mm',
+        'browser/crash_loop_detection_util.h',
+        'browser/crash_loop_detection_util.mm',
         'browser/crash_report/crash_report_background_uploader.h',
         'browser/crash_report/crash_report_background_uploader.mm',
         'browser/dom_distiller/distiller_viewer.cc',
@@ -225,8 +227,6 @@
         'browser/ui/animation_util.mm',
         'browser/ui/background_generator.h',
         'browser/ui/background_generator.mm',
-        'browser/ui/commands/UIKit+ChromeExecuteCommand.h',
-        'browser/ui/commands/UIKit+ChromeExecuteCommand.mm',
         'browser/ui/commands/clear_browsing_data_command.h',
         'browser/ui/commands/clear_browsing_data_command.mm',
         'browser/ui/commands/generic_chrome_command.h',
@@ -240,6 +240,8 @@
         'browser/ui/commands/show_mail_composer_command.mm',
         'browser/ui/commands/show_signin_command.h',
         'browser/ui/commands/show_signin_command.mm',
+        'browser/ui/commands/UIKit+ChromeExecuteCommand.h',
+        'browser/ui/commands/UIKit+ChromeExecuteCommand.mm',
         'browser/ui/file_locations.h',
         'browser/ui/file_locations.mm',
         'browser/ui/image_util.h',

ios/chrome/ios_chrome_tests.gyp

@@ -27,6 +27,7 @@
       'sources': [
         'app/safe_mode_util_unittest.cc',
         'browser/chrome_url_util_unittest.mm',
+        'browser/crash_loop_detection_util_unittest.mm',
         'browser/experimental_flags_unittest.mm',
         'browser/geolocation/CLLocation+XGeoHeaderTest.mm',
         'browser/geolocation/location_manager_unittest.mm',