ui: Cleanup class/struct forward declarations

services/ui/ws/frame_generator_delegate.h

Index: services/ui/ws/frame_generator_delegate.h
diff --git a/services/ui/ws/frame_generator_delegate.h b/services/ui/ws/frame_generator_delegate.h
index 86f90c54f5bc7afed4e70abd536fecfce3c83c02..03fbcd043ea533975ffcc7fb096b6d8a12981cfa 100644
--- a/services/ui/ws/frame_generator_delegate.h
+++ b/services/ui/ws/frame_generator_delegate.h
@@ -5,23 +5,13 @@
 #ifndef SERVICES_UI_WS_FRAME_GENERATOR_DELEGATE_H_
 #define SERVICES_UI_WS_FRAME_GENERATOR_DELEGATE_H_
 
-#include "base/macros.h"
-#include "services/ui/display/viewport_metrics.h"
-
 namespace ui {
 namespace ws {
 
-class ServerWindow;
-
 class FrameGeneratorDelegate {
  public:
-  // Returns the root window of the display.
-  virtual ServerWindow* GetRootWindow() = 0;
-
   virtual bool IsInHighContrastMode() = 0;
 
-  virtual const display::ViewportMetrics& GetViewportMetrics() const = 0;
-
  protected:
   virtual ~FrameGeneratorDelegate() {}
 };