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

chrome/browser/ui/cocoa/vertical_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.
 
 #include "base/mac/scoped_nsobject.h"
-#import "chrome/browser/ui/cocoa/cocoa_test_helper.h"
+#import "chrome/browser/ui/cocoa/test/cocoa_test_helper.h"
 #import "chrome/browser/ui/cocoa/vertical_gradient_view.h"
 
 namespace {
 
 class VerticalGradientViewTest : public CocoaTest {
  public:
   VerticalGradientViewTest() {
     NSRect frame = NSMakeRect(0, 0, 50, 27);
     base::scoped_nsobject<VerticalGradientView> view(
         [[VerticalGradientView alloc] initWithFrame:frame]);
     view_ = view.get();
     [[test_window() contentView] addSubview:view_];
   }
 
   VerticalGradientView* view_;
 };
 
 TEST_VIEW(VerticalGradientViewTest, view_);
 
 } // namespace