Service CreateNewWindow on the UI thread with a new mojo interface

chrome/browser/android/webapps/single_tab_mode_tab_helper.h

 // 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.
 
 #ifndef CHROME_BROWSER_ANDROID_WEBAPPS_SINGLE_TAB_MODE_TAB_HELPER_H_
 #define CHROME_BROWSER_ANDROID_WEBAPPS_SINGLE_TAB_MODE_TAB_HELPER_H_
 
-#include <stdint.h>
-
-#include <set>
-
-#include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "chrome/browser/ui/blocked_content/blocked_window_params.h"
-#include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 
-// Registers and unregisters the IDs of renderers in single tab mode, which
-// are disallowed from opening new windows via
-// ChromeContentBrowserClient::CanCreateWindow().
+namespace content {
+class WebContents;
+}
+
+// Tracks tabs in single tab mode, which are disallowed from opening new windows
+// via ChromeContentBrowserClient::CanCreateWindow().
 class SingleTabModeTabHelper
-    : public content::WebContentsObserver,
-      public content::WebContentsUserData<SingleTabModeTabHelper> {
+    : public content::WebContentsUserData<SingleTabModeTabHelper> {
  public:
-  // Checks if the ID pair is blocked from creating new windows. IO-thread only.
-  static bool IsRegistered(int32_t process_id, int32_t routing_id);
+  ~SingleTabModeTabHelper() override;
 
-  ~SingleTabModeTabHelper() override;
+  bool block_all_new_windows() const { return block_all_new_windows_; }
 
   // Handles opening the given URL through the TabModel.
   void HandleOpenUrl(const BlockedWindowParams& params);
 
   // Permanently block this WebContents from creating new windows -- there is no
   // current need to allow toggling this flag on or off.
   void PermanentlyBlockAllNewWindows();
 
-  // content::WebContentsObserver
-  void RenderFrameCreated(content::RenderFrameHost* render_frame_host) override;
-  void RenderFrameDeleted(content::RenderFrameHost* render_frame_host) override;
-
  private:
   explicit SingleTabModeTabHelper(content::WebContents* web_contents);
   friend class content::WebContentsUserData<SingleTabModeTabHelper>;
 
-  bool block_all_new_windows_;
+  content::WebContents* web_contents_;
+  bool block_all_new_windows_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(SingleTabModeTabHelper);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_WEBAPPS_SINGLE_TAB_MODE_TAB_HELPER_H_