Create c/b/ui/cocoa/test and move test files to there

chrome/browser/ui/cocoa/background_gradient_view_unittest.mm

 // Copyright (c) 2011 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 <Cocoa/Cocoa.h>
 
 #include "base/mac/scoped_nsobject.h"
 #import "chrome/browser/ui/cocoa/background_gradient_view.h"
-#import "chrome/browser/ui/cocoa/cocoa_test_helper.h"
+#import "chrome/browser/ui/cocoa/test/cocoa_test_helper.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 
 // Since BackgroundGradientView doesn't do any drawing by default, we
 // create a subclass to call its draw method for us.
 @interface BackgroundGradientSubClassTest : BackgroundGradientView
 @end
 
 @implementation BackgroundGradientSubClassTest
 
@@ skipping 20 matching lines @@
 
 TEST_VIEW(BackgroundGradientViewTest, view_)
 
 // Test drawing, mostly to ensure nothing leaks or crashes.
 TEST_F(BackgroundGradientViewTest, DisplayWithDivider) {
   [view_ setShowsDivider:YES];
   [view_ display];
 }
 
 }  // namespace