Look again. The stars are now diamonds.

 - To create diamonds while still using canvas.drawPoints(),
   we now generate stars in a square field large enough to
   entirely cover the screen even if we rotate it by 45°.
 - Added a bunch more stars to ensure that a goodly amount
   of them are still visible on screen.
 - PlatLogoActivity is now a convenient HDR test: if your
   display is capable of COLOR_MODE_HDR, stars at higher
   parallax planes will be progressively brighter,
   continuing past normal brightness up to 2.0f.
 - Similarly, on longpress the entire screen will fade up to
   a bright 2.0f-intensity white.

Flag: EXEMPT bugfixes and small tweaks
Test: adb shell am start -n android/com.android.internal.app.PlatLogoActivity
      adb shell input keycombination -t 10000 SPACE SPACE # SPAAAAACE!
Change-Id: I072bc46761c97cafa49fa77bab5761e57eaabd5e