Remove DisplayChangeObserver ash dependencies.

ash/display/display_change_observer_chromeos.h

Index: ash/display/display_change_observer_chromeos.h
diff --git a/ash/display/display_change_observer_chromeos.h b/ash/display/display_change_observer_chromeos.h
index cbaa57623320b4b134d4b24f43db49b438e25cc0..35a76d25833de772fe192c6746cb71740a22788d 100644
--- a/ash/display/display_change_observer_chromeos.h
+++ b/ash/display/display_change_observer_chromeos.h
@@ -7,26 +7,30 @@
 
 #include <stdint.h>
 
+#include <memory>
 #include <vector>
 
 #include "ash/ash_export.h"
-#include "ash/common/shell_observer.h"
 #include "base/macros.h"
 #include "ui/display/chromeos/display_configurator.h"
+#include "ui/display/manager/display_string_provider.h"
 #include "ui/display/manager/managed_display_info.h"
 #include "ui/events/devices/input_device_event_observer.h"
 
+namespace display {
+class DisplayManager;
+}
+
 namespace ash {
 
 class DisplayMode;
 class DisplaySnapshot;
 
-// An object that observes changes in display configuration and
-// update DisplayManagers.
+// An object that observes changes in display configuration and updates
+// DisplayManager.
 class DisplayChangeObserver : public ui::DisplayConfigurator::StateController,
                               public ui::DisplayConfigurator::Observer,
-                              public ui::InputDeviceEventObserver,
-                              public ShellObserver {
+                              public ui::InputDeviceEventObserver {
  public:
   // Returns the mode list for internal display.
   ASH_EXPORT static display::ManagedDisplayInfo::ManagedDisplayModeList
@@ -38,9 +42,18 @@ class DisplayChangeObserver : public ui::DisplayConfigurator::StateController,
   ASH_EXPORT static display::ManagedDisplayInfo::ManagedDisplayModeList
   GetExternalManagedDisplayModeList(const ui::DisplaySnapshot& output);
 
-  DisplayChangeObserver();
+  explicit DisplayChangeObserver(
+      std::unique_ptr<display::DisplayStringProvider> string_provider);
   ~DisplayChangeObserver() override;
 
+  void set_display_manager(display::DisplayManager* display_manager) {
+    display_manager_ = display_manager;
+  }
+
+  void set_display_configurator(ui::DisplayConfigurator* display_configurator) {
+    display_configurator_ = display_configurator;
+  }
+
   // ui::DisplayConfigurator::StateController overrides:
   ui::MultipleDisplayState GetStateForDisplayIds(
       const ui::DisplayConfigurator::DisplayStateList& outputs) const override;
@@ -57,13 +70,14 @@ class DisplayChangeObserver : public ui::DisplayConfigurator::StateController,
   // Overriden from ui::InputDeviceEventObserver:
   void OnTouchscreenDeviceConfigurationChanged() override;
 
-  // Overriden from ShellObserver:
-  void OnAppTerminating() override;
-
   // Exposed for testing.
   ASH_EXPORT static float FindDeviceScaleFactor(float dpi);
 
  private:
+  std::unique_ptr<display::DisplayStringProvider> string_provider_;
+  display::DisplayManager* display_manager_ = nullptr;
+  ui::DisplayConfigurator* display_configurator_ = nullptr;
+
   DISALLOW_COPY_AND_ASSIGN(DisplayChangeObserver);
 };