Move CrTrackingArea from chrome/browser/ui/cocoa to ui/base/cocoa.

ui/base/cocoa/tracking_area.mm

Index: ui/base/cocoa/tracking_area.mm
diff --git a/chrome/browser/ui/cocoa/tracking_area.mm b/ui/base/cocoa/tracking_area.mm
similarity index 97%
rename from chrome/browser/ui/cocoa/tracking_area.mm
rename to ui/base/cocoa/tracking_area.mm
index 004695bc7dedd8b5d5d2ebee6fd75ed146ed6a57..474d120345182cab1ad4d00ccb95cc1f578fea94 100644
--- a/chrome/browser/ui/cocoa/tracking_area.mm
+++ b/ui/base/cocoa/tracking_area.mm
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#import "chrome/browser/ui/cocoa/tracking_area.h"
+#import "ui/base/cocoa/tracking_area.h"
 
 #include "base/logging.h"
 
@@ -109,6 +109,8 @@
 
 // Scoper //////////////////////////////////////////////////////////////////////
 
+namespace ui {
+
 ScopedCrTrackingArea::ScopedCrTrackingArea(CrTrackingArea* tracking_area)
     : tracking_area_(tracking_area) {
 }
@@ -124,3 +126,5 @@ void ScopedCrTrackingArea::reset(CrTrackingArea* tracking_area) {
 CrTrackingArea* ScopedCrTrackingArea::get() const {
   return tracking_area_.get();
 }
+
+}  // namespace ui