Add a new hw.lcd.density hardware property to AVD configuration files.
This value can be overriden with the already existing -dpi-device <value> option.

The value is mapped to one of 120,160 and 240, then set to the boot-time property
named qemu.sf.lcd_density used by the framework to properly select assets and/or
resize them at runtime.

This means that "emulator -dpi-device 130" will select 120 lcd_density, or
"emulator -dpi-device 220" will select a 240 one.
diff --git a/android/avd/hw-config-defs.h b/android/avd/hw-config-defs.h
index 3e7cec6..7fcf732 100644
--- a/android/avd/hw-config-defs.h
+++ b/android/avd/hw-config-defs.h
@@ -136,6 +136,13 @@
   "Cache partition size",
   "")
 
+HWCFG_INT(
+  hw_lcd_density,
+  "hw.lcd.density",
+  160,
+  "Abstracted LCD density",
+  "Must be one of 120, 160 or 240. A value used to roughly describe the density of the LCD screen for automatic resource/asset selection.")
+
 #undef HWCFG_INT
 #undef HWCFG_BOOL
 #undef HWCFG_DISKSIZE