Revert of Replace TabModel with WebStateList in GoogleLandingController.

ios/chrome/browser/ui/ntp/new_tab_page_header_view.mm

 // Copyright 2014 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/ui/ntp/new_tab_page_header_view.h"
 
 #include "base/logging.h"
 #include "base/mac/scoped_nsobject.h"
 #import "ios/chrome/browser/tabs/tab_model.h"
 #import "ios/chrome/browser/tabs/tab_model_observer.h"
 #import "ios/chrome/browser/ui/image_util.h"
 #import "ios/chrome/browser/ui/ntp/google_landing_data_source.h"
 #import "ios/chrome/browser/ui/ntp/new_tab_page_header_constants.h"
 #import "ios/chrome/browser/ui/ntp/new_tab_page_toolbar_controller.h"
 #import "ios/chrome/browser/ui/uikit_ui_util.h"
 #import "ios/chrome/common/material_timing.h"
 #include "ios/chrome/grit/ios_theme_resources.h"
 #import "ui/gfx/ios/uikit_util.h"
 
 namespace {
 
 const CGFloat kOmniboxImageBottomInset = 1;
 const CGFloat kHintLabelSidePadding = 12;
 const CGFloat kMaxConstraintConstantDiff = 5;
 
 }  // namespace
 
-@interface NewTabPageHeaderView () {
+@interface NewTabPageHeaderView ()<TabModelObserver> {
   base::scoped_nsobject<NewTabPageToolbarController> _toolbarController;
+  base::scoped_nsobject<TabModel> _tabModel;
   base::scoped_nsobject<UIImageView> _searchBoxBorder;
   base::scoped_nsobject<UIImageView> _shadow;
 }
 
 @end
 
 @implementation NewTabPageHeaderView
 
 - (instancetype)initWithFrame:(CGRect)frame {
   self = [super initWithFrame:frame];
   if (self) {
     self.clipsToBounds = YES;
   }
   return self;
 }
 
 - (void)dealloc {
+  [_tabModel removeObserver:self];
   [super dealloc];
 }
 
 - (UIView*)toolBarView {
   return [_toolbarController view];
 }
 
 - (ToolbarController*)relinquishedToolbarController {
   ToolbarController* relinquishedToolbarController = nil;
   if ([[_toolbarController view] isDescendantOfView:self]) {
     // Only relinquish the toolbar controller if it's in the hierarchy.
     relinquishedToolbarController = _toolbarController.get();
   }
   return relinquishedToolbarController;
 }
 
 - (void)reparentToolbarController {
   [self addSubview:[_toolbarController view]];
 }
 
 - (void)addToolbarWithDataSource:(id<GoogleLandingDataSource>)dataSource {
   DCHECK(!_toolbarController);
   DCHECK(dataSource);
 
   _toolbarController.reset([[NewTabPageToolbarController alloc]
       initWithToolbarDelegate:[dataSource toolbarDelegate]
                       focuser:dataSource]);
   _toolbarController.get().readingListModel = [dataSource readingListModel];
+  [_tabModel removeObserver:self];
+  _tabModel.reset([[dataSource tabModel] retain]);
+  [self addTabModelObserver];
 
   UIView* toolbarView = [_toolbarController view];
   CGRect toolbarFrame = self.bounds;
   toolbarFrame.size.height = ntp_header::kToolbarHeight;
   toolbarView.frame = toolbarFrame;
   [toolbarView setAutoresizingMask:UIViewAutoresizingFlexibleWidth];
   [self hideToolbarViewsForNewTabPage];
 
   [self setAutoresizingMask:UIViewAutoresizingFlexibleWidth];
   [self addSubview:[_toolbarController view]];
 }
 
 - (void)hideToolbarViewsForNewTabPage {
   [_toolbarController hideViewsForNewTabPage:YES];
 };
 
-- (void)setToolbarTabCount:(int)tabCount {
-  [_toolbarController setTabCount:tabCount];
+- (void)addTabModelObserver {
+  [_tabModel addObserver:self];
+  [_toolbarController setTabCount:[_tabModel count]];
 }
 
 - (void)addViewsToSearchField:(UIView*)searchField {
   [searchField setBackgroundColor:[UIColor whiteColor]];
   UIImage* searchBorderImage =
       StretchableImageNamed(@"ntp_google_search_box", 12, 12);
   _searchBoxBorder.reset([[UIImageView alloc] initWithImage:searchBorderImage]);
   [_searchBoxBorder setFrame:[searchField bounds]];
   [_searchBoxBorder setAutoresizingMask:UIViewAutoresizingFlexibleWidth |
                                         UIViewAutoresizingFlexibleHeight];
   [searchField insertSubview:_searchBoxBorder atIndex:0];
 
   UIImage* fullBleedShadow = NativeImage(IDR_IOS_TOOLBAR_SHADOW_FULL_BLEED);
   _shadow.reset([[UIImageView alloc] initWithImage:fullBleedShadow]);
   CGRect shadowFrame = [searchField bounds];
   shadowFrame.origin.y =
       searchField.bounds.size.height - kOmniboxImageBottomInset;
   shadowFrame.size.height = fullBleedShadow.size.height;
   [_shadow setFrame:shadowFrame];
   [_shadow setUserInteractionEnabled:NO];
   [_shadow setAutoresizingMask:UIViewAutoresizingFlexibleWidth |
                                UIViewAutoresizingFlexibleTopMargin];
   [searchField addSubview:_shadow];
   [_shadow setAlpha:0];
 }
 
+- (void)tabModelDidChangeTabCount:(TabModel*)model {
+  DCHECK(model == _tabModel);
+  [_toolbarController setTabCount:[_tabModel count]];
+}
+
 - (void)updateSearchField:(UIView*)searchField
          withInitialFrame:(CGRect)initialFrame
        subviewConstraints:(NSArray*)constraints
                 forOffset:(CGFloat)offset {
   // The scroll offset at which point |searchField|'s frame should stop growing.
   CGFloat maxScaleOffset =
       self.frame.size.height - ntp_header::kMinHeaderHeight;
   // The scroll offset at which point |searchField|'s frame should start
   // growing.
   CGFloat startScaleOffset = maxScaleOffset - ntp_header::kAnimationDistance;
@@ skipping 29 matching lines @@
 }
 
 - (void)fadeOutShadow {
   [UIView animateWithDuration:ios::material::kDuration1
                    animations:^{
                      [_shadow setAlpha:0];
                    }];
 }
 
 @end