Refactor BrowserViewRenderer to support page visibility

android_webview/native/aw_contents.cc

Index: android_webview/native/aw_contents.cc
diff --git a/android_webview/native/aw_contents.cc b/android_webview/native/aw_contents.cc
index ebe83fb8ef87c46cfe2d219171291063d054f796..0c69e17546c7ad60a3ee1820e11161a228ac8507 100644
--- a/android_webview/native/aw_contents.cc
+++ b/android_webview/native/aw_contents.cc
@@ -863,6 +863,10 @@ void AwContents::OnDetachedFromWindow(JNIEnv* env, jobject obj) {
   browser_view_renderer_.OnDetachedFromWindow();
 }
 
+bool AwContents::IsVisible(JNIEnv* env, jobject obj) {
+  return browser_view_renderer_.IsVisible();
+}
+
 void AwContents::DetachFunctorFromView() {
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);