Feed back to the ServiceTabLauncher when the tab has been created.

chrome/browser/android/service_tab_launcher.h

 // Copyright 2015 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_SERVICE_TAB_LAUNCHER_H_
 #define CHROME_BROWSER_ANDROID_SERVICE_TAB_LAUNCHER_H_
 
+#include <map>
+
 #include "base/android/jni_android.h"
 #include "base/callback_forward.h"
 #include "base/memory/singleton.h"
 
 namespace content {
 class BrowserContext;
 struct OpenURLParams;
 class WebContents;
 }
 
 namespace chrome {
 namespace android {
 
 // Launcher for creating new tabs on Android from a background service, where
-// there may not necessarily be an Activity or a tab model at all.
+// there may not necessarily be an Activity or a tab model at all. When the
+// tab has been launched, the user of this class will be informed with the
+// content::WebContents instance associated with the tab.
 class ServiceTabLauncher {
+  using TabLaunchedCallback = base::Callback<void(content::WebContents*)>;
+
  public:
   // Returns the singleton instance of the service tab launcher.
   static ServiceTabLauncher* GetInstance();
 
   // Launches a new tab when we're in a Service rather than in an Activity.
   // |callback| will be invoked with the resulting content::WebContents* when
   // the tab is avialable. This method must only be called from the UI thread.
   void LaunchTab(content::BrowserContext* browser_context,
                  const content::OpenURLParams& params,
-                 const base::Callback<void(content::WebContents*)>& callback);
+                 const TabLaunchedCallback& callback);
+
+  // To be called when the tab for |request_id| has launched, with the
+  // associated |web_contents|. The WebContents must not yet have started
+  // the provisional load for the main frame of the navigation.
+  void OnTabLaunched(int request_id, content::WebContents* web_contents);
 
   static bool RegisterServiceTabLauncher(JNIEnv* env);
 
  private:
   friend struct DefaultSingletonTraits<ServiceTabLauncher>;
 
   ServiceTabLauncher();
   ~ServiceTabLauncher();
 
   base::android::ScopedJavaGlobalRef<jobject> java_object_;
 
+  std::map<int, TabLaunchedCallback> tab_launched_callbacks_;

[mlamouri (slow - plz ping), 2015/02/19 14:51:17]

Could you use an IDMap? It will prevent having to make a copy of the callback
and you can delegate the unique ID work to it.

[Bernhard Bauer, 2015/02/19 15:03:05]

FTR: Copies of callbacks are cheap, as they just contain a scoped_refptr to a
refcounted immutable object.

[Peter Beverloo, 2015/02/19 16:03:07]

Done.

+  int last_request_id_;
+
   DISALLOW_COPY_AND_ASSIGN(ServiceTabLauncher);
 };
 
 }  // namespace android
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_ANDROID_SERVICE_TAB_LAUNCHER_H_