Fixes memory leak

ui/gfx/image/image_mac_unittest.mm

 // 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 <Cocoa/Cocoa.h>
 
 #include "base/logging.h"
 #include "base/memory/scoped_nsobject.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/gfx/image/image.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/image/image_unittest_util.h"
 
 namespace {
 
 class ImageMacTest : public testing::Test {
  public:
   void CreateBitmapImageRep(int width, int height,

[Nico, 2012/06/12 15:31:50]

nit: "Create" suggests that the caller is responsible for releasing the result,
maybe rename to just "BitmapImageRep()"?

                             NSBitmapImageRep** image_rep) {
-    *image_rep = [[NSBitmapImageRep alloc]
+    *image_rep = [[[NSBitmapImageRep alloc]
         initWithBitmapDataPlanes:NULL
                       pixelsWide:width
                       pixelsHigh:height
                    bitsPerSample:8
                  samplesPerPixel:3
                         hasAlpha:NO
                         isPlanar:NO
                   colorSpaceName:NSDeviceRGBColorSpace
                     bitmapFormat:0
                      bytesPerRow:0
-                    bitsPerPixel:0];
+                    bitsPerPixel:0]
+                 autorelease];
   }
 };
 
 namespace gt = gfx::test;
 
 TEST_F(ImageMacTest, NSImageWithResizedNSImageRepToImageSkia) {
   const int kWidth1x = 10;
   const int kHeight1x = 12;
   const int kWidth2x = 20;
   const int kHeight2x = 24;
@@ skipping 95 matching lines @@
     EXPECT_EQ([image_rep_1 size].height, kHeight2x);
     EXPECT_EQ([image_rep_2 size].width, kWidth1x);
     EXPECT_EQ([image_rep_2 size].height, kHeight1x);
   }
 
   // Cast to NSImage* should create a second representation.
   EXPECT_EQ(2u, image.RepresentationCount());
 }
 
 } // namespace