[WebView] Add a new flushVisualState API to AwContents.

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 2a9a35f91f331150de1ec2da90f48a63b31fb181..1559ef55824f35490b8d6809d76b9828ef7ead5a 100644
--- a/android_webview/native/aw_contents.cc
+++ b/android_webview/native/aw_contents.cc
@@ -1046,6 +1046,22 @@ void AwContents::EnableOnNewPicture(JNIEnv* env,
   browser_view_renderer_.EnableOnNewPicture(enabled);
 }
 
+namespace {
+void FlushVisualStateCallback(ScopedJavaGlobalRef<jobject>* callback,
+                              bool result) {
+  JNIEnv* env = AttachCurrentThread();
+  Java_AwContents_flushVisualStateCallback(env, callback->obj(), !result);
+}
+}  // namespace
+
+void AwContents::FlushVisualState(JNIEnv* env, jobject obj, jobject callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  ScopedJavaGlobalRef<jobject>* j_callback = new ScopedJavaGlobalRef<jobject>();
+  j_callback->Reset(env, callback);
+  web_contents_->GetMainFrame()->FlushVisualState(
+      base::Bind(&FlushVisualStateCallback, base::Owned(j_callback)));
+}
+
 void AwContents::ClearView(JNIEnv* env, jobject obj) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   browser_view_renderer_.ClearView();