Add Android Chromoting client keyboard input

remoting/android/java/src/org/chromium/chromoting/jni/JniInterface.java

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chromoting.jni;
 
 import android.app.Activity;
 import android.app.AlertDialog;
 import android.content.Context;
 import android.content.DialogInterface;
@@ skipping 161 matching lines @@
      * Sets the redraw callback to the provided functor. Provide a value of null whenever the
      * window is no longer visible so that we don't continue to draw onto it.
      */
     public static void provideRedrawCallback(Runnable redrawCallback) {
         sRedrawCallback = redrawCallback;
     }
 
     /** Forces the native graphics thread to redraw to the canvas. */
     public static boolean redrawGraphics() {
         synchronized(JniInterface.class) {
-            if (!sConnected) return false;
+            if (!sConnected || sRedrawCallback == null) return false;
         }
 
         scheduleRedrawNative();
         return true;
     }
 
     /** Performs the redrawing callback. This is a no-op if the window isn't visible. */
     private static void redrawGraphicsInternal() {
         if (sRedrawCallback != null)
             sRedrawCallback.run();
@@ skipping 22 matching lines @@
 
     /** Moves the mouse cursor, possibly while clicking. */
     public static void mouseAction(int x, int y, int whichButton, boolean buttonDown) {
         if (!sConnected) {
             return;
         }
 
         mouseActionNative(x, y, whichButton, buttonDown);
     }
 
+    /** Presses and releases the specified key. */
+    public static void keyboardAction(int keyCode, boolean keyDown) {
+        if (!sConnected) {
+            return;
+        }
+
+        keyboardActionNative(keyCode, keyDown);
+    }
+
     /** Performs the native response to the user's PIN. */
     private static native void authenticationResponse(String pin);
 
     /** Schedules a redraw on the native graphics thread. */
     private static native void scheduleRedrawNative();
 
     /** Passes mouse information to the native handling code. */
     private static native void mouseActionNative(int x, int y, int whichButton, boolean buttonDown);
+
+    /** Passes key press information to the native handling code. */
+    private static native void keyboardActionNative(int keyCode, boolean keyDown);
 }