[Android] Fix a flicker in stopping Chrome

content/shell/android/java/src/org/chromium/content_shell/ShellManager.java

 // Copyright 2012 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.content_shell;
 
 import android.app.Activity;
 import android.content.Context;
 import android.util.AttributeSet;
 import android.view.LayoutInflater;
@@ skipping 60 matching lines @@
         assert window != null;
         mWindow = window;
         mContentViewRenderView = new ContentViewRenderView(getContext()) {
             @Override
             protected void onReadyToRender() {
                 if (sStartup) {
                     mActiveShell.loadUrl(mStartupUrl);
                     sStartup = false;
                 }
             }
+
+            @Override
+            protected void onWindowVisibilityChanged(int visibility) {
+                if (visibility == View.GONE && mActiveShell != null) {
+                    ContentViewCore contentViewCore = mActiveShell.getContentViewCore();
+                    if (contentViewCore != null) contentViewCore.onHide();
+                }
+                super.onWindowVisibilityChanged(visibility);
+            }
         };
         mContentViewRenderView.onNativeLibraryLoaded(window);
     }
 
     /**
      * @return The window used to generate all shells.
      */
     public WindowAndroid getWindow() {
         return mWindow;
     }
@@ skipping 66 matching lines @@
         if (shellView.getParent() == null) return;
         ContentViewCore contentViewCore = shellView.getContentViewCore();
         if (contentViewCore != null) contentViewCore.onHide();
         shellView.setContentViewRenderView(null);
         removeView(shellView);
     }
 
     private static native void nativeInit(Object shellManagerInstance);
     private static native void nativeLaunchShell(String url);
 }