Revert of Use ChromeBrowserStateManager instead of BrowserListIOS.

ios/chrome/browser/ui/browser_list_ios.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/ui/browser_list_ios.h"
+
+#include "ios/chrome/browser/browser_state/chrome_browser_state.h"
+#include "ios/chrome/browser/tabs/tab_model.h"
+
+BrowserListIOS::BrowserVector* BrowserListIOS::browsers_;
+
+void BrowserListIOS::AddBrowser(id<BrowserIOS> browser) {
+  EnsureBrowsersIsValid();
+  DCHECK(browser);
+  browsers_->push_back(browser);
+}
+
+void BrowserListIOS::RemoveBrowser(id<BrowserIOS> browser) {
+  if (!browsers_)
+    return;
+  DCHECK(browser);
+  const iterator remove_browser =
+      std::find(browsers_->begin(), browsers_->end(), browser);
+  if (remove_browser != browsers_->end())
+    browsers_->erase(remove_browser);
+}
+
+id<BrowserIOS> BrowserListIOS::GetLastActiveWithBrowserState(
+    ios::ChromeBrowserState* browser_state) {
+  DCHECK(browser_state);
+  for (const_iterator i = BrowserListIOS::begin(); i != BrowserListIOS::end();
+       ++i) {
+    if ([*i browserState] == browser_state)
+      return *i;
+  }
+  return NULL;
+}
+
+BrowserListIOS::const_iterator BrowserListIOS::begin() {
+  EnsureBrowsersIsValid();
+  return browsers_->begin();
+}
+
+BrowserListIOS::const_iterator BrowserListIOS::end() {
+  EnsureBrowsersIsValid();
+  return browsers_->end();
+}
+
+// static
+bool BrowserListIOS::IsOffTheRecordSessionActive() {
+  for (const_iterator i = BrowserListIOS::begin(); i != BrowserListIOS::end();
+       ++i) {
+    // Unlike desktop, an Incognito browser can exist but be empty, so filter
+    // that case out.
+    if ([*i browserState] && [*i browserState]->IsOffTheRecord() &&
+        ![[*i tabModel] isEmpty])
+      return true;
+  }
+  return false;
+}
+
+void BrowserListIOS::EnsureBrowsersIsValid() {
+  if (browsers_)
+    return;
+  browsers_ = new BrowserVector;
+}