Fix a few spelling errors in comments.

ui/aura/window_unittest.cc

 // Copyright (c) 2012 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 "ui/aura/window.h"
 
 #include <string>
 #include <utility>
 #include <vector>
 
@@ skipping 1853 matching lines @@
   // notification.
   scoped_ptr<Window> w3(CreateTestWindowWithId(3, root_window()));
   EXPECT_EQ("added=0 removed=0", WindowObserverCountStateAndClear());
 
   // Similarly destroying w3 shouldn't notify us either.
   w3.reset();
   EXPECT_EQ("added=0 removed=0", WindowObserverCountStateAndClear());
   w1->RemoveObserver(this);
 }
 
-// Test if OnWindowVisibilityChagned is invoked with expected
+// Test if OnWindowVisibilityChanged is invoked with expected
 // parameters.
 TEST_F(WindowObserverTest, WindowVisibility) {
   scoped_ptr<Window> w1(CreateTestWindowWithId(1, root_window()));
   scoped_ptr<Window> w2(CreateTestWindowWithId(1, w1.get()));
   w2->AddObserver(this);
 
   // Hide should make the window invisible and the passed visible
   // parameter is false.
   w2->Hide();
   EXPECT_FALSE(!GetVisibilityInfo());
@@ skipping 1035 matching lines @@
 
   EXPECT_TRUE(animator.get());
   EXPECT_FALSE(animator->is_animating());
   EXPECT_TRUE(observer.animation_completed());
   EXPECT_FALSE(observer.animation_aborted());
   animator->RemoveObserver(&observer);
 }
 
 }  // namespace test
 }  // namespace aura