Listen to changes to touch input devices

In https://codereview.chromium.org/2964823002 the OobeDisplayChooser
started using the DeviceDataManager to look for touchscreen devices when
searching for a good primary display to use during OOBE.

On device cold boot the DeviceDataManager has not yet found any
touchscreen devices at the time OobeUi::ShowOobeUI() is called (likely
due to lower level systems not being fully initialized).

This CL make LoginDisplayHostImpl an observer of changes to connected
touchscreen devices, re-triggering the OobeDisplayChooser when the
DeviceDataManager is notified of the connected touchscreens. This
overcomes the timing issues on cold boot.

Bug: 738885
Change-Id: Iae488ddc9428b7c5e74d36cf18e35ba3d1235bbd
Reviewed-on: https://chromium-review.googlesource.com/569958Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Commit-Queue: Felix Ekblom <felixe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#487007}

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

@@ -99,6 +99,7 @@
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
+#include "ui/events/devices/device_data_manager.h"
 #include "ui/events/event_handler.h"
 #include "ui/events/event_utils.h"
 #include "ui/gfx/geometry/rect.h"
@@ -384,6 +385,8 @@ LoginDisplayHostImpl::LoginDisplayHostImpl(const gfx::Rect& wallpaper_bounds)
 
   display::Screen::GetScreen()->AddObserver(this);
 
+  ui::DeviceDataManager::GetInstance()->AddObserver(this);
+
   // We need to listen to CLOSE_ALL_BROWSERS_REQUEST but not APP_TERMINATING
   // because/ APP_TERMINATING will never be fired as long as this keeps
   // ref-count. CLOSE_ALL_BROWSERS_REQUEST is safe here because there will be no
@@ -493,6 +496,7 @@ LoginDisplayHostImpl::~LoginDisplayHostImpl() {
   DBusThreadManager::Get()->GetSessionManagerClient()->RemoveObserver(this);
   CrasAudioHandler::Get()->RemoveAudioObserver(this);
   display::Screen::GetScreen()->RemoveObserver(this);
+  ui::DeviceDataManager::GetInstance()->RemoveObserver(this);
 
   if (login_view_ && login_window_)
     login_window_->RemoveRemovalsObserver(this);
@@ -1017,6 +1021,13 @@ void LoginDisplayHostImpl::OnDisplayMetricsChanged(
   }
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// LoginDisplayHostImpl, ui::InputDeviceEventObserver
+void LoginDisplayHostImpl::OnTouchscreenDeviceConfigurationChanged() {
+  if (GetOobeUI())
+    GetOobeUI()->OnDisplayConfigurationChanged();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // LoginDisplayHostImpl, views::WidgetRemovalsObserver:
 void LoginDisplayHostImpl::OnWillRemoveView(views::Widget* widget,

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

@@ -28,6 +28,7 @@
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "ui/display/display_observer.h"
+#include "ui/events/devices/input_device_event_observer.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/views/widget/widget_removals_observer.h"
 #include "ui/wm/public/scoped_drag_drop_disabler.h"
@@ -51,6 +52,7 @@ class LoginDisplayHostImpl : public LoginDisplayHost,
                              public chromeos::SessionManagerClient::Observer,
                              public chromeos::CrasAudioHandler::AudioObserver,
                              public display::DisplayObserver,
+                             public ui::InputDeviceEventObserver,
                              public views::WidgetRemovalsObserver,
                              public chrome::MultiUserWindowManager::Observer {
  public:
@@ -122,6 +124,9 @@ class LoginDisplayHostImpl : public LoginDisplayHost,
   void OnDisplayMetricsChanged(const display::Display& display,
                                uint32_t changed_metrics) override;
 
+  // Overridden from ui::InputDeviceEventObserver
+  void OnTouchscreenDeviceConfigurationChanged() override;
+
   // Overriden from views::WidgetRemovalsObserver:
   void OnWillRemoveView(views::Widget* widget, views::View* view) override;