Implement issue #1780928: Need support hiding nav keys.

This implements support for devices whose hardware can hide
their navigation keys.  It works much like the existing keyboardHidden
configuration, and for compatibility uses the same configuration
change bit.

Also add FLAG_TURN_ON_SCREEN for windows, which has the system
cause the screen to be turned on when the window is displayed.
Great fun when used with FLAG_SHOW_WHEN_LOCKED!

Change-Id: I0b867f19af85cfd8786a14cea194b34f7bdd9b7a
diff --git a/core/java/android/view/WindowManager.java b/core/java/android/view/WindowManager.java
index 8c12656..f67c4aa 100644
--- a/core/java/android/view/WindowManager.java
+++ b/core/java/android/view/WindowManager.java
@@ -500,6 +500,12 @@
          */
         public static final int FLAG_SHOW_WALLPAPER = 0x00100000;
         
+        /** Window flag: when set as a window is being added or made
+         * visible, once the window has been shown then the system will
+         * poke the power manager's user activity (as if the user had woken
+         * up the device) to turn the screen on. */
+        public static final int FLAG_TURN_SCREEN_ON = 0x00200000;
+        
         /** Window flag: special flag to limit the size of the window to be
          * original size ([320x480] x density). Used to create window for applications
          * running under compatibility mode.