Tell system server whether the app handled input events.

Refactored ViewRoot, NativeActivity and related classes to tell the
dispatcher whether an input event was actually handled by the application.

This will be used to move more of the global default key processing
into the system server instead of the application.

Change-Id: If06b98b6f45c543e5ac5b1eae2b3baf9371fba28

services/java/com/android/server/InputManager.java

@@ -418,6 +418,14 @@ public class InputManager {
                     action, flags, keyCode, scanCode, metaState, repeatCount, policyFlags);
         }
         
+        @SuppressWarnings("unused")
+        public boolean dispatchUnhandledKey(InputChannel focus, int action,
+                int flags, int keyCode, int scanCode, int metaState, int repeatCount,
+                int policyFlags) {
+            return mWindowManagerService.mInputMonitor.dispatchUnhandledKey(focus,
+                    action, flags, keyCode, scanCode, metaState, repeatCount, policyFlags);
+        }
+        
         @SuppressWarnings("unused")
         public boolean checkInjectEventsPermission(int injectorPid, int injectorUid) {
             return mContext.checkPermission(