Renames SessionChanges and SessionCellData to have a TabSwitcher prefix.

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

Index: ios/chrome/browser/ui/tab_switcher/tab_switcher_model_unittest.mm
diff --git a/ios/chrome/browser/ui/tab_switcher/tab_switcher_model_unittest.mm b/ios/chrome/browser/ui/tab_switcher/tab_switcher_model_unittest.mm
index 58c4cf9258d051d9f6110b95193f460072183cc0..7eccd8ef2365bf1b85b0c84316713e5e0904bf34 100644
--- a/ios/chrome/browser/ui/tab_switcher/tab_switcher_model_unittest.mm
+++ b/ios/chrome/browser/ui/tab_switcher/tab_switcher_model_unittest.mm
@@ -9,7 +9,6 @@
 #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"
@@ -17,13 +16,6 @@
 
 namespace {
 
-// A lightweight SessionChanges.
-struct LightSessionChanges {
-  std::vector<int> updates;
-  std::vector<int> deletions;
-  std::vector<int> insertions;
-};
-
 // A lightweight DistantTab.
 class LightDT {
  public: