Extract TabModelObservers from tab_model.mm to its own file.

ios/chrome/browser/tabs/tab_model.mm

 // Copyright 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.
 
 #import "ios/chrome/browser/tabs/tab_model.h"
 
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
-#import "base/ios/crb_protocol_observers.h"
 #include "base/logging.h"
 #import "base/mac/scoped_nsobject.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/user_metrics.h"
 #include "base/metrics/user_metrics_action.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "components/sessions/core/serialized_navigation_entry.h"
 #include "components/sessions/core/session_id.h"
 #include "components/sessions/core/tab_restore_service.h"
 #include "components/sessions/ios/ios_live_tab.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/chrome_url_constants.h"
 #import "ios/chrome/browser/chrome_url_util.h"
 #import "ios/chrome/browser/metrics/tab_usage_recorder.h"
 #include "ios/chrome/browser/sessions/ios_chrome_tab_restore_service_factory.h"
 #import "ios/chrome/browser/sessions/session_service.h"
 #import "ios/chrome/browser/sessions/session_window.h"
 #import "ios/chrome/browser/snapshots/snapshot_cache.h"
 #include "ios/chrome/browser/tab_parenting_global_observer.h"
 #import "ios/chrome/browser/tabs/tab.h"
 #import "ios/chrome/browser/tabs/tab_model_list.h"
-#import "ios/chrome/browser/tabs/tab_model_observer.h"
+#import "ios/chrome/browser/tabs/tab_model_observers.h"
 #import "ios/chrome/browser/tabs/tab_model_order_controller.h"
 #import "ios/chrome/browser/tabs/tab_model_synced_window_delegate.h"
 #import "ios/chrome/browser/xcallback_parameters.h"
 #import "ios/web/navigation/crw_session_certificate_policy_manager.h"
 #import "ios/web/navigation/crw_session_controller.h"
 #include "ios/web/public/browser_state.h"
 #include "ios/web/public/certificate_policy_cache.h"
 #include "ios/web/public/navigation_item.h"
 #import "ios/web/public/navigation_manager.h"
 #include "ios/web/public/web_thread.h"
@@ skipping 57 matching lines @@
   task_tracker->PostTaskAndReply(
       task_runner.get(), FROM_HERE,
       base::Bind(&web::CertificatePolicyCache::ClearCertificatePolicies,
                  policy_cache),
       base::Bind(&RestoreCertificatePolicyCacheFromModel, policy_cache,
                  base::Unretained(tab_model)));
 }
 
 }  // anonymous namespace
 
-@interface TabModelObservers : CRBProtocolObservers<TabModelObserver>
-@end
-@implementation TabModelObservers
-@end
-
 @interface TabModel ()<TabUsageRecorderDelegate> {
   // Array of |Tab| objects.
   base::scoped_nsobject<NSMutableArray> _tabs;
   // Maintains policy for where new tabs go and the selection when a tab
   // is removed.
   base::scoped_nsobject<TabModelOrderController> _orderController;
   // The delegate for sync.
   std::unique_ptr<TabModelSyncedWindowDelegate> _syncedWindowDelegate;
   // Currently selected tab. May be nil.
   base::WeakNSObject<Tab> _currentTab;
@@ skipping 122 matching lines @@
 
 - (NSUInteger)count {
   return [_tabs count];
 }
 
 - (instancetype)initWithSessionWindow:(SessionWindowIOS*)window
                        sessionService:(SessionServiceIOS*)service
                          browserState:(ios::ChromeBrowserState*)browserState {
   if ((self = [super init])) {
     _observers.reset([[TabModelObservers
         observersWithProtocol:@protocol(TabModelObserver)] retain]);

[rohitrao (ping after 24h), 2017/02/13 19:24:28]

Could you instead use the new +[TabModelObservers observers] method?

[sdefresne, 2017/02/14 10:11:31]

Oh, yeah this is why I added the +observers method. Thank you for catching this.

 
     _browserState = browserState;
     DCHECK(_browserState);
 
     // There must be a valid session service defined to consume session windows.
     DCHECK(service);
     _sessionService.reset([service retain]);
 
     // Normal browser states are the only ones to get tab restore. Tab sync
     // handles incognito browser states by filtering on profile, so it's
@@ skipping 808 matching lines @@
   web::NavigationManager::WebLoadParams params(URL);
   params.referrer = referrer;
   params.transition_type = ui::PAGE_TRANSITION_TYPED;
   [[tab webController] loadWithParams:params];
   [tab webController].webUsageEnabled = webUsageEnabled_;
   [self insertTab:tab atIndex:index];
   return tab;
 }
 
 @end