Refactor creation of SadTabView into a tab helper object

ios/chrome/browser/tabs/tab.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.h"
 
 #import <CoreLocation/CoreLocation.h>
 #import <UIKit/UIKit.h>
 
 #include <utility>
@@ skipping 83 matching lines @@
 #include "ios/chrome/browser/ui/commands/ios_command_ids.h"
 #import "ios/chrome/browser/ui/commands/open_url_command.h"
 #import "ios/chrome/browser/ui/commands/show_signin_command.h"
 #import "ios/chrome/browser/ui/downloads/download_manager_controller.h"
 #import "ios/chrome/browser/ui/fullscreen_controller.h"
 #import "ios/chrome/browser/ui/open_in_controller.h"
 #import "ios/chrome/browser/ui/overscroll_actions/overscroll_actions_controller.h"
 #import "ios/chrome/browser/ui/prerender_delegate.h"
 #import "ios/chrome/browser/ui/reader_mode/reader_mode_checker.h"
 #import "ios/chrome/browser/ui/reader_mode/reader_mode_controller.h"
-#import "ios/chrome/browser/ui/sad_tab/sad_tab_view.h"
 #include "ios/chrome/browser/ui/ui_util.h"
 #import "ios/chrome/browser/web/auto_reload_bridge.h"
 #import "ios/chrome/browser/web/external_app_launcher.h"
 #import "ios/chrome/browser/web/navigation_manager_util.h"
 #import "ios/chrome/browser/web/passkit_dialog_provider.h"
 #include "ios/chrome/browser/web/print_observer.h"
 #import "ios/chrome/browser/xcallback_parameters.h"
 #include "ios/chrome/grit/ios_strings.h"
 #include "ios/public/provider/chrome/browser/chrome_browser_provider.h"
 #import "ios/public/provider/chrome/browser/native_app_launcher/native_app_metadata.h"
@@ skipping 1823 matching lines @@
     UMA_HISTOGRAM_ENUMERATION(
         kRendererTerminationStateHistogram, static_cast<int>(tab_state),
         static_cast<int>(
             RendererTerminationTabState::TERMINATION_TAB_STATE_COUNT));
     if ([parentTabModel_ tabUsageRecorder])
       [parentTabModel_ tabUsageRecorder]->RendererTerminated(self, visible_);
   }
 
   if (visible_) {
     if (!applicationIsNotActive) {
-      base::WeakNSObject<Tab> weakSelf(self);
-      base::scoped_nsobject<SadTabView> sadTabView(
-          [[SadTabView alloc] initWithReloadHandler:^{
-            base::scoped_nsobject<Tab> strongSelf([weakSelf retain]);
-
-            // |check_for_repost| is true because this is called from SadTab and
-            // explicitly initiated by the user.
-            [strongSelf navigationManager]->Reload(web::ReloadType::NORMAL,
-                                                   true /* check_for_repost */);
-          }]);
-      base::scoped_nsobject<CRWContentView> contentView(
-          [[CRWGenericContentView alloc] initWithView:sadTabView]);
-      self.webState->ShowTransientContentView(contentView);
       [fullScreenController_ disableFullScreen];
     }
   } else {
     [self.webController requirePageReload];
   }
   // Returning to the app (after the renderer crashed in the background) and
   // having the page reload is much less confusing for the user.
   // Note: Given that the tab is visible, calling |requirePageReload| will not
   // work when the app becomes active because there is nothing to trigger
   // a view redisplay in that scenario.
@@ skipping 110 matching lines @@
   [inputAccessoryViewController_ wasShown];
 }
 
 - (void)wasHidden {
   visible_ = NO;
   [self updateFullscreenWithToolbarVisible:YES];
   [self.webController wasHidden];
   [inputAccessoryViewController_ wasHidden];
 }
 
+#pragma mark - SadTabTabHelperDelegate
+
+- (BOOL)isTabVisibleForTabHelper:(SadTabTabHelper*)tabHelper {
+  BOOL shouldBeActive = YES;

[Eugene But (OOO till 7-30), 2017/04/11 15:17:00]

How about this?:

UIApplicationState state = UIApplication.sharedApplication.applicationState;
return visible_ && !IsApplicationStateNotActive(state);

[kkhorimoto, 2017/04/11 17:38:02]

+1, or at least rename |shouldBeActive| to |isTabVisible|

[peterlaurens, 2017/04/11 21:57:26]

Done, thanks! 

To explain why I wrote this like this:
• I wanted to make this as readable as possible and avoid a double-negative
• I have preferred to use local variables that are set and then returned, as 
I've found that can help logging or making quick changes to force a state
during debugging.

I understand that this is less applicable here though, so happy to make this
change!

+  UIApplicationState state = UIApplication.sharedApplication.applicationState;
+  bool applicationIsActive = !IsApplicationStateNotActive(state);
+  shouldBeActive = (visible_ && applicationIsActive);
+  return shouldBeActive;
+}
+
 @end
 
 #pragma mark - TestingSupport
 
 @implementation Tab (TestingSupport)
 
 - (void)replaceExternalAppLauncher:(id)externalAppLauncher {
   externalAppLauncher_.reset([externalAppLauncher retain]);
 }
 
 - (TabModel*)parentTabModel {
   return parentTabModel_;
 }
 
 - (FormInputAccessoryViewController*)inputAccessoryViewController {
   return inputAccessoryViewController_.get();
 }
 
 @end