Add ability for Widgets to override the DefaultThemeProvider

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

Index: chrome/browser/chromeos/login/ui/lock_window_aura.cc
diff --git a/chrome/browser/chromeos/login/ui/lock_window_aura.cc b/chrome/browser/chromeos/login/ui/lock_window_aura.cc
index 83d35260e65ca6e30ff10f8293b19bbb5613b05f..cff6a7b33d4c316ba96894ba87e7943e96728268 100644
--- a/chrome/browser/chromeos/login/ui/lock_window_aura.cc
+++ b/chrome/browser/chromeos/login/ui/lock_window_aura.cc
@@ -7,6 +7,10 @@
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "base/command_line.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/themes/theme_service.h"
+#include "chrome/browser/themes/theme_service_factory.h"
+#include "chrome/browser/ui/ash/multi_user/multi_user_util.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
 
@@ -61,6 +65,13 @@ void LockWindowAura::Init() {
   params.parent =
       ash::Shell::GetContainer(ash::Shell::GetPrimaryRootWindow(),
                                ash::kShellWindowId_LockScreenContainer);
+  // On login screen and logged in as an anonymous user you might not get a
+  // profile. Which indicates that multi-user is not active and an anonymous

[tdanderson, 2015/09/09 17:38:58]

nit: change . to , between first two sentences (here and elsewhere in the CL)

+  // profile is in use. Take the active profile to find the theme.
+  Profile* profile = multi_user_util::GetProfileFromWindow(params.parent);
+  if (!profile)
+    profile = ProfileManager::GetActiveUserProfile();
+  params.theme_provider = ThemeServiceFactory::GetForProfile(profile);
   views::Widget::Init(params);
   SetVisibilityAnimationTransition(views::Widget::ANIMATE_NONE);
 }