Remove setupTabModel from BrowserViewWrangler.

Replace it with 2 methods:
1- restoreSessionToBrowser
2- addObserversToWebStateList

Bug: 1049335
Change-Id: I7099e8fdfdc023fdd71bde00cd1384213690dd1c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2040008Reviewed-by: Mark Cogan <marq@chromium.org>
Commit-Queue: Mohammad Refaat <mrefaat@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738989}

ios/chrome/browser/ui/main/BUILD.gn

@@ -97,6 +97,7 @@ source_set("main") {
     "//ios/chrome/browser/main",
     "//ios/chrome/browser/reading_list",
     "//ios/chrome/browser/sessions",
+    "//ios/chrome/browser/sessions:restoration_agent",
     "//ios/chrome/browser/sessions:serialisation",
     "//ios/chrome/browser/sessions:session_service",
     "//ios/chrome/browser/store_kit",

ios/chrome/browser/ui/main/browser_view_wrangler.mm

@@ -15,6 +15,7 @@
 #import "ios/chrome/browser/main/browser_list.h"
 #import "ios/chrome/browser/main/browser_list_factory.h"
 #import "ios/chrome/browser/sessions/session_ios.h"
+#import "ios/chrome/browser/sessions/session_restoration_browser_agent.h"
 #import "ios/chrome/browser/sessions/session_service_ios.h"
 #import "ios/chrome/browser/sessions/session_window_ios.h"
 #import "ios/chrome/browser/tabs/tab_model.h"
@@ -127,12 +128,12 @@
 @property(nonatomic, strong, readwrite)
     DeviceSharingManager* deviceSharingManager;
 
-// Sets up the given |tabModel| for use.  If |restorePersistedState| is YES,
-// then any existing tabs that have been saved for |browserState| will be
-// loaded; otherwise, the tab model will be left empty.
-- (void)setUpTabModel:(TabModel*)tabModel
-         withBrowserState:(ChromeBrowserState*)browserState
-    restorePersistedState:(BOOL)restorePersistedState;
+// Restore session to the given |browser|, any existing tabs that have been
+// saved for the |browser| will be loaded.
+- (void)restoreSessionToBrowser:(Browser*)browser;
+
+// Add the common observers to the browser's |webStateList|.
+- (void)addObserversToWebStateList:(WebStateList*)webStateList;
 
 // Setters for the main and otr Browsers.
 - (void)setMainBrowser:(std::unique_ptr<Browser>)browser;
@@ -182,9 +183,8 @@
   BrowserList* browserList =
       BrowserListFactory::GetForBrowserState(_mainBrowser->GetBrowserState());
   browserList->AddBrowser(_mainBrowser.get());
-  [self setUpTabModel:_mainBrowser->GetTabModel()
-           withBrowserState:_browserState
-      restorePersistedState:YES];
+  [self restoreSessionToBrowser:_mainBrowser.get()];
+  [self addObserversToWebStateList:_mainBrowser->GetWebStateList()];
 
   // Follow loaded URLs in the main tab model to send those in case of
   // crashes.
@@ -445,50 +445,45 @@
   BrowserList* browserList =
       BrowserListFactory::GetForBrowserState(browser->GetBrowserState());
   browserList->AddIncognitoBrowser(browser.get());
+  if (restorePersistedState)
+    [self restoreSessionToBrowser:browser.get()];
+
+  [self addObserversToWebStateList:browser->GetWebStateList()];
 
-  [self setUpTabModel:browser->GetTabModel()
-           withBrowserState:otrBrowserState
-      restorePersistedState:restorePersistedState];
   return browser;
 }
 
-- (void)setUpTabModel:(TabModel*)tabModel
-         withBrowserState:(ChromeBrowserState*)browserState
-    restorePersistedState:(BOOL)restorePersistedState {
-  DCHECK_EQ(0U, tabModel.count);
+- (BrowserCoordinator*)coordinatorForBrowser:(Browser*)browser {
+  BrowserCoordinator* coordinator =
+      [[BrowserCoordinator alloc] initWithBaseViewController:nil
+                                                     browser:browser];
+  coordinator.applicationCommandHandler = _applicationCommandEndpoint;
+  coordinator.browsingDataCommandHandler = _browsingDataCommandEndpoint;
+  coordinator.appURLLoadingService = _appURLLoadingService;
+  return coordinator;
+}
+
+- (void)restoreSessionToBrowser:(Browser*)browser {
   SessionWindowIOS* sessionWindow = nil;
-  if (restorePersistedState) {
-    // Load existing saved tab model state.
-    NSString* statePath =
-        base::SysUTF8ToNSString(browserState->GetStatePath().AsUTF8Unsafe());
+  NSString* statePath = base::SysUTF8ToNSString(
+      browser->GetBrowserState()->GetStatePath().AsUTF8Unsafe());
   SessionIOS* session =
       [[SessionServiceIOS sharedService] loadSessionFromDirectory:statePath];
   if (session) {
     DCHECK_EQ(session.sessionWindows.count, 1u);
     sessionWindow = session.sessionWindows[0];
   }
-
-    [tabModel restoreSessionWindow:sessionWindow forInitialRestore:YES];
-  }
-
-  // Add observers.
-  _activeWebStateObservationForwarders[tabModel.webStateList] =
-      std::make_unique<ActiveWebStateObservationForwarder>(
-          tabModel.webStateList, _activeWebStateObserver.get());
-  tabModel.webStateList->AddObserver(_webStateListObserver.get());
-  tabModel.webStateList->AddObserver(_webStateListForwardingObserver.get());
-
-  breakpad::MonitorTabStateForWebStateList(tabModel.webStateList);
+  SessionRestorationBrowserAgent::FromBrowser(browser)->RestoreSessionWindow(
+      sessionWindow);
 }
 
-- (BrowserCoordinator*)coordinatorForBrowser:(Browser*)browser {
-  BrowserCoordinator* coordinator =
-      [[BrowserCoordinator alloc] initWithBaseViewController:nil
-                                                     browser:browser];
-  coordinator.applicationCommandHandler = _applicationCommandEndpoint;
-  coordinator.browsingDataCommandHandler = _browsingDataCommandEndpoint;
-  coordinator.appURLLoadingService = _appURLLoadingService;
-  return coordinator;
+- (void)addObserversToWebStateList:(WebStateList*)webStateList {
+  _activeWebStateObservationForwarders[webStateList] =
+      std::make_unique<ActiveWebStateObservationForwarder>(
+          webStateList, _activeWebStateObserver.get());
+  webStateList->AddObserver(_webStateListObserver.get());
+  webStateList->AddObserver(_webStateListForwardingObserver.get());
+  breakpad::MonitorTabStateForWebStateList(webStateList);
 }
 
 @end