Add density to display viewports

This CL adds display density in DPI to the display viewports. This will
be used by InputManager to scale cursor movement on the display based on
the density value.

Bug: 367662715
Test: presubmit and manual
Flag: com.android.input.flags.scale_cursor_speed_with_dpi
Change-Id: Idfa4ebff81a84cb6f1d73429e2b0b6925173e177