[Mac] Create CrTrackingArea and use it in TabStripController.

chrome/browser/ui/cocoa/tabs/tab_strip_controller.h

Index: chrome/browser/ui/cocoa/tabs/tab_strip_controller.h
diff --git a/chrome/browser/ui/cocoa/tabs/tab_strip_controller.h b/chrome/browser/ui/cocoa/tabs/tab_strip_controller.h
index 96a8e6bfa2c0d45001b30f8ed56e9da26bb328f1..69ffd4181dffe9e6beb98f89acddfbe3f8fe053f 100644
--- a/chrome/browser/ui/cocoa/tabs/tab_strip_controller.h
+++ b/chrome/browser/ui/cocoa/tabs/tab_strip_controller.h
@@ -15,6 +15,7 @@
 #import "chrome/browser/ui/cocoa/url_drop_target.h"
 #import "third_party/GTM/AppKit/GTMWindowSheetController.h"
 
+@class CrTrackingArea;
 @class NewTabButton;
 @class TabContentsController;
 @class TabView;
@@ -71,7 +72,7 @@ class ToolbarModel;
   NewTabButton* newTabButton_;  // weak, obtained from the nib.
 
   // Tracks the newTabButton_ for rollovers.
-  scoped_nsobject<NSTrackingArea> newTabTrackingArea_;
+  scoped_nsobject<CrTrackingArea> newTabTrackingArea_;
   scoped_ptr<TabStripModelObserverBridge> bridge_;
   Browser* browser_;  // weak
   TabStripModel* tabStripModel_;  // weak
@@ -123,7 +124,7 @@ class ToolbarModel;
   float availableResizeWidth_;
   // A tracking area that's the size of the tab strip used to be notified
   // when the mouse moves in the tab strip
-  scoped_nsobject<NSTrackingArea> trackingArea_;
+  scoped_nsobject<CrTrackingArea> trackingArea_;
   TabView* hoveredTab_;  // weak. Tab that the mouse is hovering over
 
   // Array of subviews which are permanent (and which should never be removed),