chrome: Cleanup class/struct forward declarations

chrome/browser/android/data_usage/data_use_tab_model.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_DATA_USAGE_DATA_USE_TAB_MODEL_H_
 #define CHROME_BROWSER_ANDROID_DATA_USAGE_DATA_USE_TAB_MODEL_H_
 
 #include <stddef.h>
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/callback_forward.h"
 #include "base/containers/hash_tables.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/threading/thread_checker.h"
 #include "base/time/time.h"
 #include "chrome/browser/android/data_usage/tab_data_use_entry.h"
 #include "components/sessions/core/session_id.h"
 #include "url/gurl.h"
 
 namespace base {
-class SingleThreadTaskRunner;
 class TickClock;
 }
 
 namespace content {
 class NavigationEntry;
 }
 
 namespace chrome {
 
 namespace android {
 
 class DataUseMatcher;
-class ExternalDataUseObserverBridge;
 
 // Models tracking and labeling of data usage within each Tab. Within each tab,
 // the model tracks the data use of a sequence of navigations in a "tracking
 // session" beginning with an entry event and ending with an exit event.
 // Typically, these events are navigations matching a URL pattern, or various
 // types of browser-initiated navigations. A single tab may have several
 // disjoint "tracking sessions" depending on the sequence of entry and exit
 // events that took place.
 class DataUseTabModel {
  public:
@@ skipping 270 matching lines @@
   base::WeakPtrFactory<DataUseTabModel> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DataUseTabModel);
 };
 
 }  // namespace android
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_ANDROID_DATA_USAGE_DATA_USE_TAB_MODEL_H_