Implement screen capture for android

base/android/java/src/org/chromium/base/BaseChromiumApplication.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.base;
 
 import android.app.Activity;
 import android.app.Application;
 import android.content.Context;
 import android.os.Bundle;
 import android.view.KeyEvent;
 import android.view.Window;
 
 /**
  * Basic application functionality that should be shared among all browser applications.
  */
 public class BaseChromiumApplication extends Application {
+    private Activity mActivity = null;
     /**
      * Interface to be implemented by listeners for window focus events.
      */
     public interface WindowFocusChangedListener {
         /**
          * Called when the window focus changes for {@code activity}.
          * @param activity The {@link Activity} that has a window focus changed event.
          * @param hasFocus Whether or not {@code activity} gained or lost focus.
          */
         public void onWindowFocusChanged(Activity activity, boolean hasFocus);
     }
 
     private ObserverList<WindowFocusChangedListener> mWindowFocusListeners =
             new ObserverList<WindowFocusChangedListener>();
 
     @Override
     public void onCreate() {
         super.onCreate();
         ApplicationStatus.initialize(this);
 
         registerActivityLifecycleCallbacks(new ActivityLifecycleCallbacks() {
             @Override
             public void onActivityCreated(final Activity activity, Bundle savedInstanceState) {
+                mActivity = activity;

[whywhat, 2015/08/17 13:58:46]

One should use the ApplicationStatus.getLastTrackedFocusedActivity for correct
activity tracking.

                 Window.Callback callback = activity.getWindow().getCallback();
                 activity.getWindow().setCallback(new WindowCallbackWrapper(callback) {
                     @Override
                     public void onWindowFocusChanged(boolean hasFocus) {
                         super.onWindowFocusChanged(hasFocus);
 
                         for (WindowFocusChangedListener listener : mWindowFocusListeners) {
                             listener.onWindowFocusChanged(activity, hasFocus);
                         }
                     }
@@ skipping 55 matching lines @@
      * Unregisters a listener from receiving window focus updates on activities in this application.
      * @param listener Listener that doesn't want to receive window focus events.
      */
     public void unregisterWindowFocusChangedListener(WindowFocusChangedListener listener) {
         mWindowFocusListeners.removeObserver(listener);
     }
 
     /** Initializes the {@link CommandLine}. */
     public void initCommandLine() {}
 
+    public Activity getActivity() {
+        return mActivity;
+    }
+
     /**
      * This must only be called for contexts whose application is a subclass of
      * {@link BaseChromiumApplication}.
      */
     @VisibleForTesting
     public static void initCommandLine(Context context) {
         ((BaseChromiumApplication) context.getApplicationContext()).initCommandLine();
     };
 }