chrome: Cleanup class/struct forward declarations

chrome/browser/android/offline_pages/background_scheduler_bridge.h

 // Copyright 2016 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_OFFLINE_PAGES_BACKGROUND_SCHEDULER_BRIDGE_H_
 #define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_BACKGROUND_SCHEDULER_BRIDGE_H_
 
 #include "components/offline_pages/background/scheduler.h"
 
 #include "base/android/jni_android.h"
 
-namespace content {
-class BrowserContext;
-}
-
 namespace offline_pages {
 namespace android {
 
 // Bridge between C++ and Java for implementing background scheduler
 // on Android.
 class BackgroundSchedulerBridge : public Scheduler {
  public:
   // Scheduler implementation.
   void Schedule(const TriggerConditions& trigger_conditions) override;
   void BackupSchedule(const TriggerConditions& trigger_conditions,
                       long delay_in_seconds) override;
   void Unschedule() override;
 
  private:
   base::android::ScopedJavaLocalRef<jobject> CreateTriggerConditions(
       JNIEnv* env,
       bool require_power_connected,
       int minimum_battery_percentage,
       bool require_unmetered_network) const;
 };
 
 bool RegisterBackgroundSchedulerBridge(JNIEnv* env);
 
 }  // namespace android
 }  // namespace offline_pages
 
 #endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_BACKGROUND_SCHEDULER_BRIDGE_H_