Upstream Chrome on iOS source code [2/11].

ios/chrome/browser/tabs/tab_model_observer.h

+// 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.
+
+#ifndef IOS_CHROME_BROWSER_TABS_TAB_MODEL_OBSERVER_H_
+#define IOS_CHROME_BROWSER_TABS_TAB_MODEL_OBSERVER_H_
+
+#import <Foundation/Foundation.h>
+
+@class Tab;
+@class TabModel;
+
+// Observers implement these methods to be alerted to changes in the model.
+// These methods are all optional.
+@protocol TabModelObserver<NSObject>
+@optional
+
+// A tab was inserted at the given index.
+- (void)tabModel:(TabModel*)model
+    didInsertTab:(Tab*)tab
+         atIndex:(NSUInteger)index
+    inForeground:(BOOL)fg;
+
+// The given tab will be removed.
+- (void)tabModel:(TabModel*)model willRemoveTab:(Tab*)tab;
+
+// A tab was removed at the given index.
+- (void)tabModel:(TabModel*)model
+    didRemoveTab:(Tab*)tab
+         atIndex:(NSUInteger)index;
+
+// A tab was moved to the given index.  |fromIndex| is guaranteed to be
+// different than |toIndex| (moves to the same index do not trigger
+// notifications).  This method is only called for moves that change the
+// relative order of tabs (for example, closing the first tab decrements all tab
+// indexes by one, but will not call this observer method).
+- (void)tabModel:(TabModel*)model
+      didMoveTab:(Tab*)tab
+       fromIndex:(NSUInteger)fromIndex
+         toIndex:(NSUInteger)toIndex;
+
+// A Tab was replaced in the model, at the given index.
+- (void)tabModel:(TabModel*)model
+    didReplaceTab:(Tab*)oldTab
+          withTab:(Tab*)newTab
+          atIndex:(NSUInteger)index;
+
+// A tab was activated.
+- (void)tabModel:(TabModel*)model
+    didChangeActiveTab:(Tab*)newTab
+           previousTab:(Tab*)previousTab
+               atIndex:(NSUInteger)index;
+
+// The number of Tabs in this TabModel changed.
+- (void)tabModelDidChangeTabCount:(TabModel*)model;
+
+// Some properties about the given tab changed, such as the URL or title.
+- (void)tabModel:(TabModel*)model didChangeTab:(Tab*)tab;
+
+// The |tab|'s snapshot was changed to |image|.
+- (void)tabModel:(TabModel*)model
+    didChangeTabSnapshot:(Tab*)tab
+               withImage:image;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_TABS_TAB_MODEL_OBSERVER_H_