[ios] Cleanup SessionServiceIOS implementation.

ios/chrome/browser/sessions/session_window_ios_unittest.mm

Index: ios/chrome/browser/sessions/session_window_ios_unittest.mm
diff --git a/ios/chrome/browser/sessions/session_window_ios_unittest.mm b/ios/chrome/browser/sessions/session_window_ios_unittest.mm
index cadd7eac9408e11a54c9628bf4391b1762c854d4..e8dcf66976e6031e9719c1f071ba1ff94b1dee4d 100644
--- a/ios/chrome/browser/sessions/session_window_ios_unittest.mm
+++ b/ios/chrome/browser/sessions/session_window_ios_unittest.mm
@@ -46,17 +46,6 @@ TEST_F(SessionWindowIOSTest, InitWithSessions) {
   EXPECT_EQ(0u, session_window.selectedIndex);
 }
 
-TEST_F(SessionWindowIOSTest, ClearSessions) {
-  SessionWindowIOS* session_window = CreateSessionWindowForTest(0u);
-
-  ASSERT_EQ(2u, [session_window.sessions count]);
-  ASSERT_EQ(0u, session_window.selectedIndex);
-
-  [session_window clearSessions];
-  EXPECT_EQ(0u, [session_window.sessions count]);
-  EXPECT_EQ(static_cast<NSUInteger>(NSNotFound), session_window.selectedIndex);
-}
-
 TEST_F(SessionWindowIOSTest, CodingEncoding) {
   SessionWindowIOS* original_session_window = CreateSessionWindowForTest(1u);