[ios] Hook up URLLoader in remote tabs for tab grid

This CL hooks up the URLLoader for remote tabs in tab grid. When the
user taps on a remote tab, the tab will be loaded and the tab will be
displayed.

Bug: 804588
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I7a6dbe200d8e806b14012d3986bbd61789cf810b
Reviewed-on: https://chromium-review.googlesource.com/1088188Reviewed-by: Sergio Collazos <sczs@chromium.org>
Reviewed-by: edchin <edchin@chromium.org>
Commit-Queue: edchin <edchin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565071}

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

@@ -23,8 +23,10 @@ source_set("tab_grid") {
     "//components/favicon/ios",
     "//ios/chrome/browser",
     "//ios/chrome/browser/browser_state",
+    "//ios/chrome/browser/sessions:serialisation",
     "//ios/chrome/browser/snapshots",
     "//ios/chrome/browser/tabs",
+    "//ios/chrome/browser/ui",
     "//ios/chrome/browser/ui/commands",
     "//ios/chrome/browser/ui/coordinators:chrome_coordinators",
     "//ios/chrome/browser/ui/main",

ios/chrome/browser/ui/tab_grid/tab_grid_coordinator.mm

@@ -4,7 +4,9 @@
 
 #import "ios/chrome/browser/ui/tab_grid/tab_grid_coordinator.h"
 
+#include "components/sessions/core/session_types.h"
 #include "ios/chrome/browser/chrome_url_constants.h"
+#include "ios/chrome/browser/sessions/session_util.h"
 #import "ios/chrome/browser/tabs/tab_model.h"
 #import "ios/chrome/browser/ui/commands/browser_commands.h"
 #import "ios/chrome/browser/ui/commands/command_dispatcher.h"
@@ -17,12 +19,16 @@
 #import "ios/chrome/browser/ui/tab_grid/tab_grid_paging.h"
 #import "ios/chrome/browser/ui/tab_grid/tab_grid_transition_handler.h"
 #import "ios/chrome/browser/ui/tab_grid/tab_grid_view_controller.h"
+#import "ios/chrome/browser/ui/url_loader.h"
+#import "ios/chrome/browser/web_state_list/web_state_list.h"
+#import "ios/chrome/browser/web_state_list/web_state_opener.h"
+#import "ios/web/public/web_state/web_state.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
-@interface TabGridCoordinator ()<TabPresentationDelegate>
+@interface TabGridCoordinator ()<TabPresentationDelegate, UrlLoader>
 // Superclass property specialized for the class that this coordinator uses.
 @property(nonatomic, weak) TabGridViewController* mainViewController;
 // Commad dispatcher used while this coordinator's view controller is active.
@@ -167,6 +173,7 @@
       self.remoteTabsMediator;
   mainViewController.remoteTabsViewController.dispatcher =
       static_cast<id<ApplicationCommands>>(self.dispatcher);
+  mainViewController.remoteTabsViewController.loader = self;
   if (self.remoteTabsMediator.browserState) {
     [self.remoteTabsMediator initObservers];
     [self.remoteTabsMediator refreshSessionsView];
@@ -312,4 +319,57 @@
 - (void)closeAllIncognitoTabs {
 }
 
+#pragma mark - UrlLoader
+
+- (void)loadSessionTab:(const sessions::SessionTab*)sessionTab {
+  WebStateList* webStateList = self.regularTabModel.webStateList;
+  std::unique_ptr<web::WebState> webState =
+      session_util::CreateWebStateWithNavigationEntries(
+          self.regularTabModel.browserState,
+          sessionTab->current_navigation_index, sessionTab->navigations);
+  webStateList->InsertWebState(webStateList->count(), std::move(webState),
+                               WebStateList::INSERT_ACTIVATE, WebStateOpener());
+  // Trigger the transition through the TabSwitcher delegate. This will in turn
+  // call back into this coordinator via the ViewControllerSwapping protocol.
+  [self.tabSwitcher.delegate tabSwitcher:self.tabSwitcher
+             shouldFinishWithActiveModel:self.regularTabModel];
+}
+
+- (void)webPageOrderedOpen:(const GURL&)url
+                  referrer:(const web::Referrer&)referrer
+              inBackground:(BOOL)inBackground
+                  appendTo:(OpenPosition)appendTo {
+  // TODO(crbug.com/850240) : Hook up open all tabs in session.
+  UIAlertController* alertController = [UIAlertController
+      alertControllerWithTitle:@"Not Yet Implemented"
+                       message:
+                           @"We are still working on this feature. In the "
+                           @"meantime, you can access this feature through the "
+                           @"overflow menu and the new tab page."
+                preferredStyle:UIAlertControllerStyleAlert];
+  [alertController
+      addAction:[UIAlertAction actionWithTitle:@"OK"
+                                         style:UIAlertActionStyleCancel
+                                       handler:nil]];
+  [self.mainViewController presentViewController:alertController
+                                        animated:YES
+                                      completion:nil];
+}
+
+- (void)webPageOrderedOpen:(const GURL&)url
+                  referrer:(const web::Referrer&)referrer
+               inIncognito:(BOOL)inIncognito
+              inBackground:(BOOL)inBackground
+                  appendTo:(OpenPosition)appendTo {
+  // This is intentionally NO-OP.
+}
+
+- (void)loadURLWithParams:(const web::NavigationManager::WebLoadParams&)params {
+  // This is intentionally NO-OP.
+}
+
+- (void)loadJavaScriptFromLocationBar:(NSString*)script {
+  // This is intentionally NO-OP.
+}
+
 @end