Add keycodes PageUp and PageDown

This is useful for applications like web browser.

Change-Id: Ie9262d5b75de87ecd0971407a7c3ce9aa6e4998e
diff --git a/include/ui/KeycodeLabels.h b/include/ui/KeycodeLabels.h
index 571e47b..749155e 100644
--- a/include/ui/KeycodeLabels.h
+++ b/include/ui/KeycodeLabels.h
@@ -114,6 +114,8 @@
     { "MEDIA_REWIND", 89 },
     { "MEDIA_FAST_FORWARD", 90 },
     { "MUTE", 91 },
+    { "PAGE_UP", 92 },
+    { "PAGE_DOWN", 93 },
 
     // NOTE: If you add a new keycode here you must also add it to:
     //   (enum KeyCode, in this file)
@@ -218,7 +220,9 @@
     kKeyCodePreviousSong = 88,
     kKeyCodeRewind = 89,
     kKeyCodeForward = 90,
-    kKeyCodeMute = 91
+    kKeyCodeMute = 91,
+    kKeyCodePageUp = 92,
+    kKeyCodePageDown = 93
 } KeyCode;
 
 static const KeycodeLabel FLAGS[] = {