Fix issue #23122445: Add 420 density

Change-Id: I15c113eb7e22f1d882db071c007224746f9d408f
diff --git a/api/current.txt b/api/current.txt
index 4b36adc..cb63aaa 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -33958,6 +33958,7 @@
     field public static final int DENSITY_280 = 280; // 0x118
     field public static final int DENSITY_360 = 360; // 0x168
     field public static final int DENSITY_400 = 400; // 0x190
+    field public static final int DENSITY_420 = 420; // 0x1a4
     field public static final int DENSITY_560 = 560; // 0x230
     field public static final int DENSITY_DEFAULT = 160; // 0xa0
     field public static final int DENSITY_HIGH = 240; // 0xf0
diff --git a/api/system-current.txt b/api/system-current.txt
index 36cd869..a9bc944 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -36250,6 +36250,7 @@
     field public static final int DENSITY_280 = 280; // 0x118
     field public static final int DENSITY_360 = 360; // 0x168
     field public static final int DENSITY_400 = 400; // 0x190
+    field public static final int DENSITY_420 = 420; // 0x1a4
     field public static final int DENSITY_560 = 560; // 0x230
     field public static final int DENSITY_DEFAULT = 160; // 0xa0
     field public static final int DENSITY_HIGH = 240; // 0xf0
diff --git a/core/java/android/util/DisplayMetrics.java b/core/java/android/util/DisplayMetrics.java
index a36e66c..9a69600 100644
--- a/core/java/android/util/DisplayMetrics.java
+++ b/core/java/android/util/DisplayMetrics.java
@@ -90,6 +90,14 @@
     public static final int DENSITY_400 = 400;
 
     /**
+     * Intermediate density for screens that sit somewhere between
+     * {@link #DENSITY_XHIGH} (320 dpi) and {@link #DENSITY_XXHIGH} (480 dpi).
+     * This is not a density that applications should target, instead relying
+     * on the system to scale their {@link #DENSITY_XXHIGH} assets for them.
+     */
+    public static final int DENSITY_420 = 420;
+
+    /**
      * Standard quantized DPI for extra-extra-high-density screens.
      */
     public static final int DENSITY_XXHIGH = 480;