ui: Cleanup class/struct forward declarations

chromecast/graphics/cast_screen.h

Index: chromecast/graphics/cast_screen.h
diff --git a/chromecast/graphics/cast_screen.h b/chromecast/graphics/cast_screen.h
index c100a892ff2a5e12aaee65a4e8ff5552d2ee9a2e..efcde628d2a573a7ccedb503d9378da6da5fe521 100644
--- a/chromecast/graphics/cast_screen.h
+++ b/chromecast/graphics/cast_screen.h
@@ -8,7 +8,7 @@
 #include "base/macros.h"
 #include "chromecast/public/graphics_types.h"
 #include "ui/display/display.h"
-#include "ui/display/screen.h"
+#include "ui/display/screen_base.h"
 
 namespace chromecast {
 namespace shell {
@@ -20,7 +20,7 @@ class CastBrowserMainParts;
 // class for necessary methods. The instantiation of CastScreen occurs in
 // CastBrowserMainParts, where its ownership is assigned to CastBrowserProcess.
 // To then subsequently access CastScreen, see CastBrowerProcess.
-class CastScreen : public display::Screen {
+class CastScreen : public display::ScreenBase {
  public:
   ~CastScreen() override;
 
@@ -28,22 +28,11 @@ class CastScreen : public display::Screen {
   gfx::Point GetCursorScreenPoint() override;
   bool IsWindowUnderCursor(gfx::NativeWindow window) override;
   gfx::NativeWindow GetWindowAtScreenPoint(const gfx::Point& point) override;
-  int GetNumDisplays() const override;
-  std::vector<display::Display> GetAllDisplays() const override;
   display::Display GetDisplayNearestWindow(gfx::NativeView view) const override;
-  display::Display GetDisplayNearestPoint(
-      const gfx::Point& point) const override;
-  display::Display GetDisplayMatching(
-      const gfx::Rect& match_rect) const override;
-  display::Display GetPrimaryDisplay() const override;
-  void AddObserver(display::DisplayObserver* observer) override;
-  void RemoveObserver(display::DisplayObserver* observer) override;
 
  private:
   CastScreen();
 
-  display::Display display_;
-
   friend class shell::CastBrowserMainParts;
 
   DISALLOW_COPY_AND_ASSIGN(CastScreen);