Increase the dim brightness.

Right now, the dim brightness is way too dim to the point where most
things aren't visible even in low indoor lighting situations. Upping
this a bit makes it still noticeably dimmer but a lot more visible in
normal usage. It may be worth increasing further, but this is a good
place to start.

Bug: 65346115
Test: wait for the device to dim, see that's actually visible under 4k+
      lux ambient light.

Change-Id: Idf89f1309d7eae8d5ce4d617e6117c0f6cc76562

overlay/frameworks/base/core/res/res/values/config.xml

@@ -87,8 +87,19 @@
     <!-- Shutdown if the battery temperature exceeds (this value * 0.1) Celsius. -->
     <integer name="config_shutdownBatteryTemperature">600</integer>
 
-    <!-- Minimum screen brightness allowed by the power manager. -->
-    <integer name="config_screenBrightnessDim">4</integer>
+    <!-- Screen brightness used to dim the screen when the user activity
+         timeout expires.  May be less than the minimum allowed brightness setting
+         that can be set by the user. -->
+    <integer name="config_screenBrightnessDim">15</integer>
+
+    <!-- Minimum allowable screen brightness to use in a very dark room.
+         This value sets the floor for the darkest possible auto-brightness
+         adjustment.  It is expected to be somewhat less than the first entry in
+         config_autoBrightnessLcdBacklightValues so as to allow the user to have
+         some range of adjustment to dim the screen further than usual in very
+         dark rooms. The contents of the screen must still be clearly visible
+         in darkness (although they may not be visible in a bright room). -->
+    <integer name="config_screenBrightnessDark">1</integer>
 
     <!-- Screen brightness when dozing. -->
     <integer name="config_screenBrightnessDoze">13</integer>