[Mac]Implement ViewID support. (third approach)

chrome/browser/cocoa/tab_strip_controller.mm

 // 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.
 
 #import "chrome/browser/cocoa/tab_strip_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <limits>
 #include <string>
@@ skipping 563 matching lines @@
 
 
 // Returns the view at the given index, using the array of TabControllers to
 // get the associated view. Returns nil if out of range.
 - (NSView*)viewAtIndex:(NSUInteger)index {
   if (index >= [tabArray_ count])
     return NULL;
   return [[tabArray_ objectAtIndex:index] view];
 }
 
+- (NSUInteger)viewsCount {
+  return [tabArray_ count];
+}
+
 // Called when the user clicks a tab. Tell the model the selection has changed,
 // which feeds back into us via a notification.
 - (void)selectTab:(id)sender {
   DCHECK([sender isKindOfClass:[NSView class]]);
   int index = [self modelIndexForTabView:sender];
   if (tabStripModel_->ContainsIndex(index))
     tabStripModel_->SelectTabContentsAt(index, true);
 }
 
 // Called when the user closes a tab. Asks the model to close the tab. |sender|
@@ skipping 1217 matching lines @@
     return;
 
   TabContentsController* tabController =
       [tabContentsArray_ objectAtIndex:index];
   TabContents* devtoolsContents = contents ?
       DevToolsWindow::GetDevToolsContents(contents) : NULL;
   [tabController showDevToolsContents:devtoolsContents];
 }
 
 @end