Remove obsolete code in TabModelOrderController.

ios/chrome/browser/tabs/tab_model_order_controller.mm

 // Copyright 2012 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/tabs/tab_model_order_controller.h"
 
 #include "base/logging.h"
 
-@implementation TabModelOrderController
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
 
-@synthesize insertionPolicy = insertionPolicy_;
+@implementation TabModelOrderController {
+  __weak TabModel* model_;  // weak, owns us

[rohitrao (ping after 24h), 2017/02/13 19:54:12]

Presumably this comment is unnecessary now?

[sdefresne, 2017/02/14 16:15:29]

Done.

+}
 
-- (id)initWithTabModel:(TabModel*)model {
+- (instancetype)initWithTabModel:(TabModel*)model {
   DCHECK(model);
-  self = [super init];
-  if (self) {
+  if ((self = [super init]))
     model_ = model;
-    insertionPolicy_ = TabModelOrderConstants::kInsertAfter;
-  }
   return self;
 }
 
 - (NSUInteger)insertionIndexForTab:(Tab*)newTab
                         transition:(ui::PageTransition)transition
                             opener:(Tab*)parentTab
                          adjacency:(TabModelOrderConstants::InsertionAdjacency)
                                        adjacency {
   if (model_.isEmpty)
     return 0;
 
-  if (PageTransitionCoreTypeIs(transition, ui::PAGE_TRANSITION_LINK) &&
-      parentTab) {
-    NSUInteger referenceIndex = [model_ indexOfTab:parentTab];
-    Tab* openLocation = nil;
-    if (insertionPolicy_ == TabModelOrderConstants::kInsertAfter) {
-      openLocation = [model_ lastTabWithOpener:parentTab];
-    } else {
-      openLocation = [model_ firstTabWithOpener:parentTab];
-    }
-    if (openLocation)
-      referenceIndex = [model_ indexOfTab:openLocation];
+  if (!parentTab)
+    return [self insertionIndexForAppending];
 
-    // If the reference tab is no longer in the model (e.g., it was closed
-    // before the open request was handled), fall through to default behavior.
-    if (referenceIndex != NSNotFound) {
-      BOOL insertAfter =
-          insertionPolicy_ == TabModelOrderConstants::kInsertAfter ||
-          adjacency == TabModelOrderConstants::kAdjacentAfter;
-      NSUInteger delta = insertAfter ? 1 : 0;
-      return referenceIndex + delta;
-    }
-  }
-  // In other cases, such as a normal new tab, open at the end.
-  return [self insertionIndexForAppending];
+  if (!PageTransitionCoreTypeIs(transition, ui::PAGE_TRANSITION_LINK))
+    return [self insertionIndexForAppending];
+
+  NSUInteger referenceIndex = [model_ indexOfTab:parentTab];
+  Tab* openLocation = openLocation = [model_ lastTabWithOpener:parentTab];

[rohitrao (ping after 24h), 2017/02/13 19:54:12]

Remove "= openLocation"?

[sdefresne, 2017/02/14 16:15:29]

Done.

+
+  // If the reference tab is no longer in the model (e.g., it was closed
+  // before the open request was handled), fall through to default behavior.
+  if (openLocation)

[rohitrao (ping after 24h), 2017/02/13 19:54:12]

Should this be !openLocation?

[sdefresne, 2017/02/14 16:15:29]

Good catch. My code was incorrect and I've fixed it.

+    return [self insertionIndexForAppending];
+
+  referenceIndex = [model_ indexOfTab:openLocation];
+  DCHECK_NE(referenceIndex, static_cast<NSUInteger>(NSNotFound));
+  return referenceIndex + 1;
 }
 
 - (NSUInteger)insertionIndexForAppending {
-  return insertionPolicy_ == TabModelOrderConstants::kInsertAfter ? model_.count
-                                                                  : 0;
+  return model_.count;
 }
 
 - (Tab*)determineNewSelectedTabFromRemovedTab:(Tab*)removedTab {
   // While the desktop version of this code deals in indices, this deals in
   // actual tabs. As a result, the tab only needs to change iff the selection
   // is the tab that's removed.
   if (removedTab != model_.currentTab)
     return model_.currentTab;
 
   const NSUInteger numberOfTabs = model_.count;
   if (numberOfTabs < 2)
     return nil;
+
   DCHECK(numberOfTabs >= 2);
   DCHECK(removedTab == model_.currentTab);
 
   // First see if the tab being removed has any "child" tabs. If it does, we
   // want to select the first in that child group, not the next tab in the same
   // group of the removed tab.
   Tab* firstChild = [model_ nextTabWithOpener:removedTab afterTab:nil];
   if (firstChild)
     return firstChild;
   Tab* parentTab = [model_ openerOfTab:removedTab];
@@ skipping 13 matching lines @@
   NSUInteger selectedIndex = [model_ indexOfTab:removedTab];
   DCHECK(selectedIndex <= numberOfTabs - 1);
   // Is the closing tab the last one? If so, return the penultimate tab.
   if (selectedIndex == numberOfTabs - 1)
     return [model_ tabAtIndex:selectedIndex - 1];
   // Otherwise return the next tab after the current tab.
   return [model_ tabAtIndex:selectedIndex + 1];
 }
 
 @end