Updates to clean up default theme and add hover states

chrome/browser/cocoa/tab_view_unittest.mm

 // Copyright (c) 2009 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/scoped_nsobject.h"
 #import "chrome/browser/cocoa/tab_view.h"
 #import "chrome/browser/cocoa/cocoa_test_helper.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 15 matching lines @@
 // Test adding/removing from the view hierarchy, mostly to ensure nothing
 // leaks or crashes.
 TEST_F(TabViewTest, AddRemove) {
   EXPECT_EQ(cocoa_helper_.contentView(), [view_ superview]);
   [view_.get() removeFromSuperview];
   EXPECT_FALSE([view_ superview]);
 }
 
 // Test drawing, mostly to ensure nothing leaks or crashes.
 TEST_F(TabViewTest, Display) {
+  [view_ setHoverAlpha:0.0];
+  [view_ display];
+  [view_ setHoverAlpha:0.5];
+  [view_ display];
+  [view_ setHoverAlpha:1.0];
   [view_ display];
 }
 
 // Test dragging and mouse tracking.
 TEST_F(TabViewTest, MouseTracking) {
   // TODO(pinkerton): Test dragging out of window
 }
 
 }  // namespace