Renames SessionChanges and SessionCellData to have a TabSwitcher prefix.

ios/chrome/browser/ui/tab_switcher/tab_switcher_header_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_header_view.h"
 
 #import "base/ios/weak_nsobject.h"
 #include "base/logging.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/metrics/user_metrics_action.h"
@@ skipping 316 matching lines @@
 }
 
 - (void)setPanelSelectorAccessibility {
   NSInteger index = [self selectedIndex];
   if (index != NSNotFound)
     [_accessibilityView setAccessibilityLabel:[self panelTitleAtIndex:index]];
 }
 
 - (NSString*)panelTitleAtIndex:(NSInteger)index {
   NSIndexPath* indexPath = [NSIndexPath indexPathForItem:index inSection:0];
-  SessionCellData* sessionCellData =
+  TabSwitcherSessionCellData* sessionCellData =
       [[self dataSource] sessionCellDataAtIndex:indexPath.row];
   return sessionCellData.title;
 }
 
 #pragma mark - AccessiblePanelSelectorDelegate
 
 - (void)moveToPanelInDirection:(PanelSelectionChangeDirection)direction {
   NSInteger indexDelta = direction == RIGHT ? 1 : -1;
   NSInteger newIndex = [self selectedIndex] + indexDelta;
   newIndex = std::max<NSInteger>(newIndex, 0);
@@ skipping 18 matching lines @@
   DCHECK([self dataSource]);
   DCHECK(section == 0);
   return [[self dataSource] tabSwitcherHeaderViewSessionCount];
 }
 
 - (UICollectionViewCell*)collectionView:(UICollectionView*)collectionView
                  cellForItemAtIndexPath:(NSIndexPath*)indexPath {
   TabSwitcherHeaderCell* headerCell = [collectionView
       dequeueReusableCellWithReuseIdentifier:[TabSwitcherHeaderCell identifier]
                                 forIndexPath:indexPath];
-  SessionCellData* sessionCellData =
+  TabSwitcherSessionCellData* sessionCellData =
       [[self dataSource] sessionCellDataAtIndex:indexPath.row];
   [headerCell loadSessionCellData:sessionCellData];
   return headerCell;
 }
 
 #pragma mark - UICollectionViewDelegate
 
 - (void)collectionView:(UICollectionView*)collectionView
     didSelectItemAtIndexPath:(NSIndexPath*)indexPath {
   [self updateSelectionAtIndex:indexPath.item animated:YES];
   [[self delegate] tabSwitcherHeaderViewDidSelectSessionAtIndex:indexPath.item];
 }
 
 #pragma mark - UIScrollViewDelegate
 
 - (void)scrollViewDidScroll:(UIScrollView*)scrollView {
   [self layoutActiveSpaceIndicatorAnimated:NO];
 }
 
 @end