Remove unused parameter for -replaceTab:withTab:keepOldTabOpen:.

ios/chrome/browser/tabs/tab_model.mm

Index: ios/chrome/browser/tabs/tab_model.mm
diff --git a/ios/chrome/browser/tabs/tab_model.mm b/ios/chrome/browser/tabs/tab_model.mm
index 1db302868f2c0b6654c931fc2df8d6a773534ec9..6b405c20a727c8dc61fad8d3d6c1b578ca30a169 100644
--- a/ios/chrome/browser/tabs/tab_model.mm
+++ b/ios/chrome/browser/tabs/tab_model.mm
@@ -560,9 +560,7 @@ void CleanCertificatePolicyCache(
   [_observers tabModel:self didMoveTab:tab fromIndex:fromIndex toIndex:toIndex];
 }
 
-- (void)replaceTab:(Tab*)oldTab
-           withTab:(Tab*)newTab
-    keepOldTabOpen:(BOOL)keepOldTabOpen {
+- (void)replaceTab:(Tab*)oldTab withTab:(Tab*)newTab {
   NSUInteger index = [self indexOfTab:oldTab];
   DCHECK_NE(NSNotFound, static_cast<NSInteger>(index));
 
@@ -578,8 +576,7 @@ void CleanCertificatePolicyCache(
     [self changeSelectedTabFrom:nil to:newTab persistState:NO];
 
   [oldTab setParentTabModel:nil];
-  if (!keepOldTabOpen)
-    [oldTab close];
+  [oldTab close];
 
   // Record a tab clobber, since swapping tabs bypasses the tab code that would
   // normally log clobbers.