[ios] RootCoordinator and view controller.

ios/clean/chrome/app/steps/root_coordinator+application_step.h

Index: ios/clean/chrome/app/steps/root_coordinator+application_step.h
diff --git a/ios/clean/chrome/app/steps/root_coordinator+application_step.h b/ios/clean/chrome/app/steps/root_coordinator+application_step.h
new file mode 100644
index 0000000000000000000000000000000000000000..45588311e1a80e8a3b7a932b8df3fcc0c2b9f8d3
--- /dev/null
+++ b/ios/clean/chrome/app/steps/root_coordinator+application_step.h
@@ -0,0 +1,21 @@
+// 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.
+
+#ifndef IOS_CLEAN_CHROME_APP_STEPS_ROOT_COORDINATOR_APPLICATION_STEP_H_
+#define IOS_CLEAN_CHROME_APP_STEPS_ROOT_COORDINATOR_APPLICATION_STEP_H_
+
+#import "ios/clean/chrome/app/application_step.h"
+#import "ios/clean/chrome/browser/ui/root/root_coordinator.h"
+
+// Category on RootCoordinator to allow it to act as an application
+// step and control the root UI for the application when is starts.
+// Creates the main window and makes it key, but doesn't make it visible yet.

[lpromero, 2017/04/12 08:58:49]

Maybe this is an assumption that could be unit-tested?

[edchin, 2017/04/13 07:39:15]

Additional tests are added, but this whole assumption is not unit tested. 
We need a real browser state in order to test this better. I will update
with more tests once we have better examples of coordinator unittests.

+//  Pre:  Application phase is APPLICATION_FOREGROUNDED and the main window is
+//        key.
+//  Post: Application phase is (still) APPLICATION_FOREGROUNDED, the main window
+//        is visible and has a root view controller set.
+@interface RootCoordinator (ApplicationStep)<ApplicationStep>
+@end
+
+#endif  // IOS_CLEAN_CHROME_APP_STEPS_ROOT_COORDINATOR_APPLICATION_STEP_H_