Fix WeakPtrFactory member in LoginDisplayHostImpl

This forces WeakPtrs to be invalidated before other members' destructors run.
See the bug or the documentation of WeakPtrFactory for more information. I'm
in the process of trying to turn on a clang check for this (see the bug).

BUG=303818
R=stevenjb@chromium.org

Review URL: https://codereview.chromium.org/841103003

Cr-Commit-Position: refs/heads/master@{#311373}

chrome/browser/chromeos/login/ui/login_display_host_impl.cc

@@ -272,7 +272,6 @@ const int LoginDisplayHostImpl::kShowLoginWebUIid = 0x1111;
 
 LoginDisplayHostImpl::LoginDisplayHostImpl(const gfx::Rect& background_bounds)
     : background_bounds_(background_bounds),
-      pointer_factory_(this),
       shutting_down_(false),
       oobe_progress_bar_visible_(false),
       session_starting_(false),
@@ -288,6 +287,7 @@ LoginDisplayHostImpl::LoginDisplayHostImpl(const gfx::Rect& background_bounds)
       startup_sound_played_(false),
       startup_sound_honors_spoken_feedback_(false),
       is_observing_keyboard_(false),
+      pointer_factory_(this),
       animation_weak_ptr_factory_(this) {
   DBusThreadManager::Get()->GetSessionManagerClient()->AddObserver(this);
   CrasAudioHandler::Get()->AddAudioObserver(this);

chrome/browser/chromeos/login/ui/login_display_host_impl.h

@@ -209,8 +209,6 @@ class LoginDisplayHostImpl : public LoginDisplayHost,
 
   content::NotificationRegistrar registrar_;
 
-  base::WeakPtrFactory<LoginDisplayHostImpl> pointer_factory_;
-
   // Default LoginDisplayHost.
   static LoginDisplayHost* default_host_;
 
@@ -325,6 +323,7 @@ class LoginDisplayHostImpl : public LoginDisplayHost,
   scoped_ptr<aura::Window> login_screen_container_;
 #endif
 
+  base::WeakPtrFactory<LoginDisplayHostImpl> pointer_factory_;
   base::WeakPtrFactory<LoginDisplayHostImpl> animation_weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(LoginDisplayHostImpl);