Rework ash::CursorManager into a corewm object, to share code with desktop.

ash/test/shell_test_api.h

Index: ash/test/shell_test_api.h
diff --git a/ash/test/shell_test_api.h b/ash/test/shell_test_api.h
index 9ff7ef2ecdb12f30551856e0b0cb3c931ce1ada1..6d1fae9dac68528af34383c3c1af724360258332 100644
--- a/ash/test/shell_test_api.h
+++ b/ash/test/shell_test_api.h
@@ -14,6 +14,7 @@ class InputMethodEventFilter;
 }  // namespace views
 
 namespace ash {
+class AshCursorPlatformDelegate;
 class Shell;
 class LauncherModel;
 
@@ -36,6 +37,7 @@ public:
   internal::SystemGestureEventFilter* system_gesture_event_filter();
   internal::WorkspaceController* workspace_controller();
   internal::ScreenPositionController* screen_position_controller();
+  AshCursorPlatformDelegate* ash_cursor_platform_delegate();
   LauncherModel* launcher_model();
 
  private: