Add suuport for splitting touch events across windows.

This feature is currently used to enable dragging the start and end
selection handles of a TextView at the same time.  Could be used for
other things later.

Deleted some dead code in ArrowKeyMovementMethod and CursorControllers.

Change-Id: I930accd97ca1ca1917aab8a807db2c950fc7b409
diff --git a/core/java/android/view/WindowManager.java b/core/java/android/view/WindowManager.java
index eebbc93..9c4aefe 100644
--- a/core/java/android/view/WindowManager.java
+++ b/core/java/android/view/WindowManager.java
@@ -583,6 +583,19 @@
          * also been set.
          */
         public static final int FLAG_DISMISS_KEYGUARD = 0x00400000;
+        
+        /** Window flag: when set the window will accept for touch events
+         * outside of its bounds to be sent to other windows that also
+         * support split touch.  When this flag is not set, the first pointer
+         * that goes down determines the window to which all subsequent touches
+         * go until all pointers go up.  When this flag is set, each pointer
+         * (not necessarily the first) that goes down determines the window
+         * to which all subsequent touches of that pointer will go until that
+         * pointer goes up thereby enabling touches with multiple pointers
+         * to be split across multiple windows.
+         * 
+         * {@hide} */
+        public static final int FLAG_SPLIT_TOUCH = 0x00800000;
 
         /** Window flag: *sigh* The lock screen wants to continue running its
          * animation while it is fading.  A kind-of hack to allow this.  Maybe