Move Screen, its impls, DisplayObserver and DisplayChangeNotifier to ui/display

ui/gfx/gfx.gyp

Index: ui/gfx/gfx.gyp
diff --git a/ui/gfx/gfx.gyp b/ui/gfx/gfx.gyp
index a34c1400b66a25428597ea42d49d985e50a33619..bf073a34b97c4f192fc077413408e1bb152caa4f 100644
--- a/ui/gfx/gfx.gyp
+++ b/ui/gfx/gfx.gyp
@@ -130,6 +130,7 @@
         'android/gfx_jni_registrar.h',
         'android/java_bitmap.cc',
         'android/java_bitmap.h',
+        'android/screen_android.cc',
         'android/shared_device_display_info.cc',
         'android/shared_device_display_info.h',
         'android/view_configuration.cc',
@@ -181,10 +182,6 @@
         'color_utils.h',
         'display.cc',
         'display.h',
-        'display_change_notifier.cc',
-        'display_change_notifier.h',
-        'display_observer.cc',
-        'display_observer.h',
         'favicon_size.cc',
         'favicon_size.h',
         'font.cc',
@@ -289,12 +286,6 @@
         'scoped_ns_graphics_context_save_gstate_mac.mm',
         'scoped_ui_graphics_push_context_ios.h',
         'scoped_ui_graphics_push_context_ios.mm',
-        'screen.cc',
-        'screen.h',
-        'screen_android.cc',
-        'screen_aura.cc',
-        'screen_ios.mm',
-        'screen_mac.mm',
         'scrollbar_size.cc',
         'scrollbar_size.h',
         'selection_model.cc',
@@ -444,11 +435,6 @@
             'path.cc',
           ],
         }],
-        ['OS=="android" and use_aura==1', {
-          'sources!': [
-            'screen_android.cc',
-          ],
-        }],
         ['OS=="android" or OS=="ios"', {
           'sources!': [
             'harfbuzz_font_skia.cc',