[Android] Suppress javascript dialogs from background tabs in custom tab

components/web_contents_delegate_android/web_contents_delegate_android.cc

 // Copyright (c) 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.
 
 #include "components/web_contents_delegate_android/web_contents_delegate_android.h"
 
 #include <android/keycodes.h>
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
@@ skipping 398 matching lines @@
   if (rwhv) {
     validation_message_bubble_->SetPositionRelativeToAnchor(
         rwhv->GetRenderWidgetHost(), anchor_in_root_view);
   }
 }
 
 void WebContentsDelegateAndroid::RequestAppBannerFromDevTools(
     content::WebContents* web_contents) {
 }
 
+bool WebContentsDelegateAndroid::ShouldSuppressDialogs(
+    content::WebContents* web_contents) {
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> obj = GetJavaDelegate(env);
+  if (obj.is_null())
+    return false;
+  ScopedJavaLocalRef<jobject> jsource_contents;
+  if (web_contents)
+    jsource_contents = web_contents->GetJavaWebContents();
+  return Java_WebContentsDelegateAndroid_shouldSuppressDialogs(
+        env, obj.obj(), jsource_contents.obj());
+}
+
 }  // namespace web_contents_delegate_android