Renames SessionChanges and SessionCellData to have a TabSwitcher prefix.

ios/chrome/browser/ui/tab_switcher/tab_switcher_model_unittest.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.
 
 #include "ios/chrome/browser/ui/tab_switcher/tab_switcher_model.h"
 
 #include "base/mac/scoped_nsobject.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ios/chrome/browser/browser_state/test_chrome_browser_state.h"
 #include "ios/chrome/browser/ui/ntp/recent_tabs/synced_sessions.h"
-#include "ios/chrome/browser/ui/tab_switcher/session_changes.h"
 #import "ios/chrome/browser/ui/tab_switcher/tab_switcher_model_private.h"
 #import "ios/chrome/browser/ui/tab_switcher/tab_switcher_utils.h"
 #include "testing/platform_test.h"
 #import "third_party/ocmock/OCMock/OCMock.h"
 
 namespace {
 
-// A lightweight SessionChanges.
-struct LightSessionChanges {
-  std::vector<int> updates;
-  std::vector<int> deletions;
-  std::vector<int> insertions;
-};
-
 // A lightweight DistantTab.
 class LightDT {
  public:
   LightDT(std::string const& urlSuffix, std::string const& title = "")
       : url("http://www.foo.com/" + urlSuffix), title(title) {}
   std::string url;
   std::string title;
 };
 
 // A lightweight DistantSession.
@@ skipping 388 matching lines @@
   [delegate_ expectSessionsRemoved:@[ @1 ]];
   [delegate_ expectSessionsInserted:@[ @0 ]];
 
   [TabSwitcherModel notifyDelegate:delegate_
                    aboutChangeFrom:*old_sessions
                                 to:*new_sessions];
   [delegate_ verify];
 }
 
 }  // namespace