Fix dragging a tab out of a window when the only tabs left behind are phantom...

chrome/browser/cocoa/tab_window_controller.h

 // Copyright (c) 2010 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 CHROME_BROWSER_TAB_WINDOW_CONTROLLER_H_
 #define CHROME_BROWSER_TAB_WINDOW_CONTROLLER_H_
 
 // A class acting as the Objective-C window controller for a window that has
 // tabs which can be dragged around. Tabs can be re-arranged within the same
 // window or dragged into other TabWindowController windows. This class doesn't
@@ skipping 90 matching lines @@
 // no placeholder, it will go at the end. |controller| is the window controller
 // of a tab being dropped from a different window. It will be nil if the drag is
 // within the window, otherwise the tab is removed from that window before being
 // placed into this one. The implementation will call |-removePlaceholder| since
 // the drag is now complete.  This also calls |-layoutTabs| internally so
 // clients do not need to call it again.
 - (void)moveTabView:(NSView*)view
      fromController:(TabWindowController*)controller;
 
 // Number of tabs in the tab strip. Useful, for example, to know if we're
-// dragging the only tab in the window.
+// dragging the only tab in the window. This includes pinned tabs (both live
+// and not).
 - (NSInteger)numberOfTabs;
 
+// YES if there are tabs in the tab strip which have content, allowing for
+// the notion of tabs in the tab strip that are placeholders, or phantoms, but
+// currently have no content.
+- (BOOL)hasLiveTabs;
+
 // Return the view of the selected tab.
 - (NSView *)selectedTabView;
 
 // The title of the selected tab.
 - (NSString*)selectedTabTitle;
 
 // Called to check whether or not this controller's window has a tab strip (YES
 // if it does, NO otherwise). The default implementation returns YES.
 - (BOOL)hasTabStrip;
 
 // Get/set whether a particular tab is draggable between windows.
 - (BOOL)isTabDraggable:(NSView*)tabView;
 - (void)setTab:(NSView*)tabView isDraggable:(BOOL)draggable;
 
 // Tell the window that it needs to call performClose: as soon as the current
 // drag is complete. This prevents a window (and its overlay) from going away
 // during a drag.
 - (void)deferPerformClose;
 
 @end
 
 @interface TabWindowController(ProtectedMethods)
 // Tells the tab strip to forget about this tab in preparation for it being
 // put into a different tab strip, such as during a drop on another window.
 - (void)detachTabView:(NSView*)view;
 @end
 
 #endif  // CHROME_BROWSER_TAB_WINDOW_CONTROLLER_H_