Hook up Ctrl + '/' to SysUI for a Keyboard Shortcuts screen

This CL adds the necessary hooks between PhoneWindowManager
and SysUI to show a keyboard shortcuts screen given a specific
shortcut combination. SysUI for now just shows a Toast.

Change-Id: Icf43a81776b04a2e96a540f45b7cd3464342d679
diff --git a/services/core/java/com/android/server/policy/PhoneWindowManager.java b/services/core/java/com/android/server/policy/PhoneWindowManager.java
index 45bbf37..277b6df 100644
--- a/services/core/java/com/android/server/policy/PhoneWindowManager.java
+++ b/services/core/java/com/android/server/policy/PhoneWindowManager.java
@@ -2835,6 +2835,12 @@
                     }
                 }
             }
+        } else if (keyCode == KeyEvent.KEYCODE_SLASH && event.isMetaPressed()) {
+            if (down) {
+                if (repeatCount == 0) {
+                    showKeyboardShortcutsMenu();
+                }
+            }
         } else if (keyCode == KeyEvent.KEYCODE_ASSIST) {
             if (down) {
                 if (repeatCount == 0) {
@@ -3255,6 +3261,17 @@
         }
     }
 
+    private void showKeyboardShortcutsMenu() {
+        try {
+            IStatusBarService statusbar = getStatusBarService();
+            if (statusbar != null) {
+                statusbar.showKeyboardShortcutsMenu();
+            }
+        } catch (RemoteException e) {
+            Slog.e(TAG, "RemoteException when showing keyboard shortcuts menu", e);
+        }
+    }
+
     private void hideRecentApps(boolean triggeredFromAltTab, boolean triggeredFromHome) {
         mPreloadedRecentApps = false; // preloading no longer needs to be canceled
         try {