[ios] Moves tab_switcher code out of the ios_internal namespace.

ios/chrome/browser/ui/tab_switcher/tab_switcher_panel_view.mm

 // Copyright 2015 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/tab_switcher/tab_switcher_panel_view.h"
 
 #import "base/mac/scoped_nsobject.h"
 #import "ios/chrome/browser/ui/tab_switcher/tab_switcher_panel_cell.h"
 #import "ios/chrome/browser/ui/tab_switcher/tab_switcher_panel_collection_view_layout.h"
 
 @interface TabSwitcherPanelView () {
   base::scoped_nsobject<UICollectionView> _collectionView;
   base::scoped_nsobject<TabSwitcherPanelCollectionViewLayout>
       _collectionViewLayout;
-  ios_internal::SessionType _sessionType;
+  TabSwitcherSessionType _sessionType;
 }
 
 @end
 
 @implementation TabSwitcherPanelView
 
-- (instancetype)initWithSessionType:(ios_internal::SessionType)sessionType {
+- (instancetype)initWithSessionType:(TabSwitcherSessionType)sessionType {
   self = [super initWithFrame:CGRectZero];
   if (self) {
     _sessionType = sessionType;
     [self loadSubviews];
   }
   return self;
 }
 
 - (instancetype)initWithFrame:(CGRect)frame {
   NOTREACHED();
@@ skipping 22 matching lines @@
 }
 
 #pragma mark - Private
 
 - (void)loadSubviews {
   _collectionViewLayout.reset(
       [[TabSwitcherPanelCollectionViewLayout alloc] init]);
   _collectionView.reset([[UICollectionView alloc]
              initWithFrame:self.bounds
       collectionViewLayout:_collectionViewLayout.get()]);
-  if (_sessionType == ios_internal::SessionType::DISTANT_SESSION) {
+  if (_sessionType == TabSwitcherSessionType::DISTANT_SESSION) {
     [_collectionView registerClass:[TabSwitcherDistantSessionCell class]
         forCellWithReuseIdentifier:[TabSwitcherDistantSessionCell identifier]];
   } else {
     [_collectionView registerClass:[TabSwitcherLocalSessionCell class]
         forCellWithReuseIdentifier:[TabSwitcherLocalSessionCell identifier]];
   }
   [_collectionView setBackgroundColor:[UIColor clearColor]];
   [self addSubview:_collectionView];
   [_collectionView setAutoresizingMask:UIViewAutoresizingFlexibleHeight |
                                        UIViewAutoresizingFlexibleWidth];
 }
 
 @end