[ios] Modifying TabStrip Mediator to add a new Tab.

This CL adds the functionality to the add-new-tab-button to add the
new tab via Mediator.

Bug: 1128249,1134132
Change-Id: I4a33befc0bf5c81c2726a7183120d489b7115d9c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2542904
Commit-Queue: Nazerke Kalidolda <nazerke@google.com>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#829618}

ios/chrome/browser/ui/tab_switcher/tab_strip/BUILD.gn

@@ -26,6 +26,7 @@ source_set("tab_strip_ui") {
     "tab_strip_cell.h",
     "tab_strip_cell.mm",
     "tab_strip_consumer.h",
+    "tab_strip_consumer_delegate.h",
     "tab_strip_mediator.h",
     "tab_strip_mediator.mm",
     "tab_strip_view_controller.h",

ios/chrome/browser/ui/tab_switcher/tab_strip/tab_strip_consumer_delegate.h

+// Copyright 2020 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 IOS_CHROME_BROWSER_UI_TAB_SWITCHER_TAB_STRIP_TAB_STRIP_CONSUMER_DELEGATE_H_
+#define IOS_CHROME_BROWSER_UI_TAB_SWITCHER_TAB_STRIP_TAB_STRIP_CONSUMER_DELEGATE_H_
+
+#import <UIKit/UIKit.h>
+
+// Protocol that the tabstrip UI uses to update the model.
+@protocol TabStripConsumerDelegate
+
+// Tells the receiver to insert a new item in the tabstrip.
+- (void)addNewItem;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TAB_SWITCHER_TAB_STRIP_TAB_STRIP_CONSUMER_DELEGATE_H_

ios/chrome/browser/ui/tab_switcher/tab_strip/tab_strip_coordinator.mm

@@ -52,6 +52,7 @@
   self.mediator.webStateList = self.browser->GetWebStateList();
 
   self.tabStripViewController.faviconDataSource = self.mediator;
+  self.tabStripViewController.delegate = self.mediator;
 }
 
 - (void)stop {

ios/chrome/browser/ui/tab_switcher/tab_strip/tab_strip_mediator.h

@@ -8,12 +8,14 @@
 #import <Foundation/Foundation.h>
 
 #import "ios/chrome/browser/ui/tab_switcher/tab_strip/tab_favicon_data_source.h"
+#import "ios/chrome/browser/ui/tab_switcher/tab_strip/tab_strip_consumer_delegate.h"
 
 @protocol TabStripConsumer;
 class WebStateList;
 
 // This mediator used to manage model interaction for its consumer.
-@interface TabStripMediator : NSObject <TabFaviconDataSource>
+@interface TabStripMediator
+    : NSObject <TabFaviconDataSource, TabStripConsumerDelegate>
 
 // The WebStateList that this mediator listens for any changes on the total
 // number of Webstates.

ios/chrome/browser/ui/tab_switcher/tab_strip/tab_strip_mediator.mm

@@ -6,6 +6,7 @@
 
 #import "components/favicon/ios/web_favicon_driver.h"
 #import "ios/chrome/browser/browser_state/chrome_browser_state.h"
+#import "ios/chrome/browser/chrome_url_constants.h"
 #import "ios/chrome/browser/chrome_url_util.h"
 #import "ios/chrome/browser/tabs/tab_title_util.h"
 #import "ios/chrome/browser/ui/tab_switcher/tab_strip/tab_strip_consumer.h"
@@ -14,6 +15,8 @@
 #import "ios/chrome/browser/web_state_list/all_web_state_observation_forwarder.h"
 #import "ios/chrome/browser/web_state_list/web_state_list.h"
 #import "ios/chrome/browser/web_state_list/web_state_list_observer_bridge.h"
+#import "ios/chrome/browser/web_state_list/web_state_opener.h"
+#import "ios/web/public/navigation/navigation_manager.h"
 #import "ios/web/public/web_state.h"
 #import "ios/web/public/web_state_observer_bridge.h"
 #import "ui/gfx/image/image.h"
@@ -173,6 +176,27 @@ web::WebState* GetWebStateWithId(WebStateList* web_state_list,
   }
 }
 
+#pragma mark - TabStripConsumerDelegate
+
+- (void)addNewItem {
+  if (!self.webStateList)
+    return;
+
+  web::WebState::CreateParams params(
+      self.webStateList->GetActiveWebState()->GetBrowserState());
+  std::unique_ptr<web::WebState> webState = web::WebState::Create(params);
+
+  GURL url(kChromeUINewTabURL);
+  web::NavigationManager::WebLoadParams loadParams(url);
+  loadParams.transition_type = ui::PAGE_TRANSITION_TYPED;
+  webState->GetNavigationManager()->LoadURLWithParams(loadParams);
+
+  self.webStateList->InsertWebState(
+      base::checked_cast<int>(self.webStateList->count()), std::move(webState),
+      (WebStateList::INSERT_FORCE_INDEX | WebStateList::INSERT_ACTIVATE),
+      WebStateOpener());
+}
+
 #pragma mark - Private
 
 // Calls |-populateItems:selectedItemID:| on the consumer.

ios/chrome/browser/ui/tab_switcher/tab_strip/tab_strip_view_controller.h

@@ -11,6 +11,7 @@
 
 @class TabStripMediator;
 @protocol TabFaviconDataSource;
+@protocol TabStripConsumerDelegate;
 
 // ViewController for the TabStrip. This ViewController is contained by
 // BrowserViewController. This TabStripViewController is responsible for
@@ -19,8 +20,7 @@
     : UICollectionViewController <TabStripConsumer>
 
 @property(nonatomic, weak) id<TabFaviconDataSource> faviconDataSource;
-
-@property(nonatomic, readonly, retain) UIButton* buttonNewTab;
+@property(nonatomic, weak) id<TabStripConsumerDelegate> delegate;
 
 - (instancetype)init NS_DESIGNATED_INITIALIZER;
 

ios/chrome/browser/ui/tab_switcher/tab_strip/tab_strip_view_controller.mm

@@ -32,6 +32,7 @@ const CGFloat kNewTabButtonBottomImageInset = -2.0;
 
 @interface TabStripViewController ()
 
+@property(nonatomic, strong) UIButton* buttonNewTab;
 // The local model backing the collection view.
 @property(nonatomic, strong) NSMutableArray<TabSwitcherItem*>* items;
 // Identifier of the selected item. This value is disregarded if |self.items| is
@@ -58,24 +59,30 @@ const CGFloat kNewTabButtonBottomImageInset = -2.0;
   [self.collectionView registerClass:[TabStripCell class]
           forCellWithReuseIdentifier:kReuseIdentifier];
 
-  _buttonNewTab = [[UIButton alloc] init];
-  _buttonNewTab.translatesAutoresizingMaskIntoConstraints = NO;
-  _buttonNewTab.imageView.contentMode = UIViewContentModeCenter;
+  self.buttonNewTab = [[UIButton alloc] init];
+  self.buttonNewTab.translatesAutoresizingMaskIntoConstraints = NO;
+  self.buttonNewTab.imageView.contentMode = UIViewContentModeCenter;
   UIImage* buttonNewTabImage = [[UIImage imageNamed:@"tabstrip_new_tab"]
       imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
-  [_buttonNewTab setImage:buttonNewTabImage forState:UIControlStateNormal];
-  [_buttonNewTab.imageView setTintColor:[UIColor colorNamed:kGrey500Color]];
+  [self.buttonNewTab setImage:buttonNewTabImage forState:UIControlStateNormal];
+  [self.buttonNewTab.imageView setTintColor:[UIColor colorNamed:kGrey500Color]];
   UIEdgeInsets imageInsets = UIEdgeInsetsMake(0, kNewTabButtonLeadingImageInset,
                                               kNewTabButtonBottomImageInset, 0);
-  _buttonNewTab.imageEdgeInsets = imageInsets;
-  [self.view addSubview:_buttonNewTab];
+  self.buttonNewTab.imageEdgeInsets = imageInsets;
+  [self.view addSubview:self.buttonNewTab];
   [NSLayoutConstraint activateConstraints:@[
-    [_buttonNewTab.trailingAnchor
+    [self.buttonNewTab.trailingAnchor
         constraintEqualToAnchor:self.view.trailingAnchor],
-    [_buttonNewTab.topAnchor constraintEqualToAnchor:self.view.topAnchor],
-    [_buttonNewTab.heightAnchor constraintEqualToAnchor:self.view.heightAnchor],
-    [_buttonNewTab.widthAnchor constraintEqualToConstant:kNewTabButtonWidth],
+    [self.buttonNewTab.topAnchor constraintEqualToAnchor:self.view.topAnchor],
+    [self.buttonNewTab.heightAnchor
+        constraintEqualToAnchor:self.view.heightAnchor],
+    [self.buttonNewTab.widthAnchor
+        constraintEqualToConstant:kNewTabButtonWidth],
   ]];
+
+  [self.buttonNewTab addTarget:self
+                        action:@selector(sendNewTabCommand)
+              forControlEvents:UIControlEventTouchUpInside];
 }
 
 - (NSInteger)numberOfSectionsInCollectionView:
@@ -167,4 +174,8 @@ const CGFloat kNewTabButtonBottomImageInset = -2.0;
   return [self.items indexOfObjectPassingTest:selectedTest];
 }
 
+- (void)sendNewTabCommand {
+  [self.delegate addNewItem];
+}
+
 @end