* Move UserManager test helper classes in their own files
* Move RemoveUserDelegate to user_manager component
* Move UserManager ownership to BrowserProcessPlatformPart
* UserManager::Get() still stays but instance is explicitly initialized/cleared with instance->Initialize()|Destroy()
* ScopedUserManagerEnabler / ScopedTestUserManager classes still work
* Introduce ChromeUserManager base class (impl: ChromeUserManagerImpl)
* ChromeUserManager adds getters for MultiProfileUserController, UserImageManager, SupervisedUserManager.
All clients that were using these methods now access ChromeUserManager instance through ChromeUserManager::Get().
* FakeUserManager/MockUserManager implement ChromeUserManager
* Move *UserFlow() methods out of UserManager to ChromeUserManager
BUG=387614
TBR=thestig,benwells
Review URL: https://codereview.chromium.org/444903002
Cr-Commit-Position: refs/heads/master@{#289827}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@289827 0039d316-1c4b-4281-b951-d872f2087c98
4d3907860d