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

ios/chrome/app/safe_mode/safe_mode_coordinator.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/safe_mode/safe_mode_coordinator.h"
+
+#include "base/mac/scoped_nsobject.h"
+#import "ios/chrome/app/safe_mode/safe_mode_view_controller.h"
+#include "ios/chrome/browser/crash_loop_detection_util.h"
+
+namespace {
+const int kStartupCrashLoopThreshold = 2;
+}
+
+@interface SafeModeCoordinator ()<SafeModeViewControllerDelegate> {
+  // Weak pointer to window passed on init.
+  base::WeakNSObject<UIWindow> _window;
+  // Weak pointer backing property of the same name.
+  base::WeakNSProtocol<id<SafeModeCoordinatorDelegate>> _delegate;
+}
+
+@end
+
+@implementation SafeModeCoordinator
+
+#pragma mark - property implementation.
+
+- (id<SafeModeCoordinatorDelegate>)delegate {
+  return _delegate;
+}
+
+- (void)setDelegate:(id<SafeModeCoordinatorDelegate>)delegate {
+  _delegate.reset(delegate);
+}
+
+#pragma mark - Public class methods
+
++ (BOOL)shouldStart {
+  // Check whether there appears to be a startup crash loop. If not, don't look
+  // at anything else.
+  if (crash_util::GetFailedStartupAttemptCount() < kStartupCrashLoopThreshold)
+    return NO;
+
+  return [SafeModeViewController hasSuggestions];
+}
+
+#pragma mark - ChromeCoordinator implementation
+
+- (void)start {
+  // Create the SafeModeViewController and make it the root view controller for
+  // the window. The window has ownership of it and will dispose of it when
+  // another view controller is made root.
+  //
+  // General note: Safe mode should be safe; it should not depend on other
+  // objects being created. Be extremely conservative when adding code to this
+  // method.
+  base::scoped_nsobject<SafeModeViewController> viewController(
+      [[SafeModeViewController alloc] initWithDelegate:self]);
+  [self.window setRootViewController:viewController];
+
+  // Reset the crash count; the user may change something based on the recovery
+  // UI that will fix the crash, and having the next launch start in recovery
+  // mode would be strange.
+  crash_util::ResetFailedStartupAttemptCount();
+}
+
+// Override of ChildCoordinators method, which is not supported in this class.
+- (MutableCoordinatorArray*)childCoordinators {
+  NOTREACHED() << "Do not add child coordinators to SafeModeCoordinator.";
+  return nil;
+}
+
+#pragma mark - SafeModeViewControllerDelegate implementation
+
+- (void)startBrowserFromSafeMode {
+  [self.delegate coordinatorDidExitSafeMode:self];
+}
+
+@end