Fix custom cursor transparency compositing on MacOS

content/common/cursors/webcursor_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 "base/pickle.h"
 #include "content/common/cursors/webcursor.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/platform/WebCursorInfo.h"
 
 using blink::WebCursorInfo;
@@ skipping 204 matching lines @@
   SkPMColor testColor = SkPreMultiplyARGB(10, 255, 255, 255);
   bitmap.allocN32Pixels(1,1);
   SkAutoLockPixels bitmap_lock(bitmap);
   *bitmap.getAddr32(0, 0) = testColor;
   WebCursor::CursorInfo cursor_info;
   cursor_info.type = WebCursorInfo::TypeCustom;
   cursor_info.custom_image = bitmap;
   cursor_info.image_scale_factor = 1;
   WebCursor custom_cursor;
 
-  // This round trip will convert the cursor to unpremultiplied form
+  // This round trip will convert the cursor to unpremultiplied form.
   custom_cursor.InitFromCursorInfo(cursor_info);
   custom_cursor.GetCursorInfo(&cursor_info);
   {
     SkAutoLockPixels lock(cursor_info.custom_image);
     EXPECT_EQ(kUnpremul_SkAlphaType, cursor_info.custom_image.alphaType());
     EXPECT_EQ(testColor,
               SkPreMultiplyColor(*cursor_info.custom_image.getAddr32(0,0)));
   }
 
-  // Second round trip should not do any conversion because data is alread
-  // unpremultiplied
+  // Second round trip should not do any conversion because data is already
+  // unpremultiplied.
   custom_cursor.InitFromCursorInfo(cursor_info);
   custom_cursor.GetCursorInfo(&cursor_info);
   {
     SkAutoLockPixels lock(cursor_info.custom_image);
     EXPECT_EQ(kUnpremul_SkAlphaType, cursor_info.custom_image.alphaType());
     EXPECT_EQ(testColor,
               SkPreMultiplyColor(*cursor_info.custom_image.getAddr32(0,0)));
   }
+
+#if defined(OS_MACOSX)
+  // On MacOS, test roundtrip through NSCursor conversion.
+  WebCursor custom_cursor_copy;
+  custom_cursor_copy.InitFromNSCursor(custom_cursor.GetNativeCursor());
+  custom_cursor_copy.GetCursorInfo(&cursor_info);
+  {
+    SkAutoLockPixels lock(cursor_info.custom_image);
+    EXPECT_EQ(kUnpremul_SkAlphaType, cursor_info.custom_image.alphaType());
+    EXPECT_EQ(testColor,
+              SkPreMultiplyColor(*cursor_info.custom_image.getAddr32(0,0)));
+  }
+#endif
 }
 
 }  // namespace content