[Mac] Organize some files into chrome/browser/ui/cocoa/tab_contents/....

chrome/browser/ui/cocoa/previewable_contents_controller_unittest.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 <Cocoa/Cocoa.h>
-
-#import "base/scoped_nsobject.h"
-#include "chrome/browser/ui/cocoa/browser_test_helper.h"
-#include "chrome/browser/ui/cocoa/cocoa_test_helper.h"
-#import "chrome/browser/ui/cocoa/previewable_contents_controller.h"
-#include "testing/gtest/include/gtest/gtest.h"
-#include "testing/platform_test.h"
-
-namespace {
-
-class PreviewableContentsControllerTest : public CocoaTest {
- public:
-  virtual void SetUp() {
-    CocoaTest::SetUp();
-    controller_.reset([[PreviewableContentsController alloc] init]);
-    [[test_window() contentView] addSubview:[controller_ view]];
-  }
-
-  scoped_nsobject<PreviewableContentsController> controller_;
-};
-
-TEST_VIEW(PreviewableContentsControllerTest, [controller_ view])
-
-// TODO(rohitrao): Test showing and hiding the preview.  This may require
-// changing the interface to take in a TabContentsView* instead of a
-// TabContents*.
-
-}  // namespace
-